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5,019 results on '"Saito, K."'

1. Search for Majorana Neutrinos with the Complete KamLAND-Zen Dataset

Author

Abe, S., Araki, T., Chiba, K., Eda, T., Eizuka, M., Funahashi, Y., Furuto, A., Gando, A., Gando, Y., Goto, S., Hachiya, T., Hata, K., Ichimura, K., Ieki, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Kamei, Y., Kawada, N., Kishimoto, Y., Koga, M., Marthe, A., Matsumoto, Y., Mitsui, T., Miyake, H., Morita, D., Nakajima, R., Nakamura, K., Nakamura, R., Nakane, J., Ono, T., Ozaki, H., Saito, K., Sakai, T., Shimizu, I., Shirai, J., Shiraishi, K., Suzuki, A., Tachibana, K., Tamae, K., Watanabe, H., Watanabe, K., Yoshida, S., Umehara, S., Fushimi, K., Kotera, K., Urano, Y., Berger, B. E., Fujikawa, B. K., Learned, J. G., Maricic, J., Fu, Z., Ghosh, S., Smolsky, J., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Dell'Oro, S., O'Donnell, T., Detwiler, J. A., Enomoto, S., Decowski, M. P., Weerman, K. M., Grant, C., Penek, O., Song, H., Li, A., Axani, S. N., Garcia, M., and Sarfraz, M.

Subjects
High Energy Physics - Experiment
Abstract

We present a search for neutrinoless double-beta ($0\nu\beta\beta$) decay of $^{136}$Xe using the full KamLAND-Zen 800 dataset with 745 kg of enriched xenon, corresponding to an exposure of $2.097$ ton yr of $^{136}$Xe. This updated search benefits from a more than twofold increase in exposure, recovery of photo-sensor gain, and reduced background from muon-induced spallation of xenon. Combining with the search in the previous KamLAND-Zen phase, we obtain a lower limit for the $0\nu\beta\beta$ decay half-life of $T_{1/2}^{0\nu} > 3.8 \times 10^{26}$ yr at 90% C.L., a factor of 1.7 improvement over the previous limit. The corresponding upper limits on the effective Majorana neutrino mass are in the range 28-122 meV using phenomenological nuclear matrix element calculations., Comment: arXiv admin note: text overlap with arXiv:2203.02139

Published
2024

2. Technological developments and accelerator improvements for the FRIB beam power ramp-up

Author

Wei, J, Alleman, C, Ao, H, Arend, B, Barofsky, D, Beher, S, Bollen, G, Bultman, N, Casagrande, F, Chang, W, Choi, Y, Cogan, S, Cole, P, Compton, C, Cortesi, M, Curtin, J, Davidson, K, Di Carlo, S, Du, X, Elliott, K, Ewert, B, Facco, A, Fila, A, Fukushima, K, Ganni, V, Ganshyn, A, Ginter, T, Glasmacher, T, Gonzalez, A, Hao, Y, Hartung, W, Hasan, N, Hausmann, M, Holland, K, Hseuh, HC, Ikegami, M, Jager, D, Jones, S, Joseph, N, Kanemura, T, Kim, SH, Knowles, C, Konomi, T, Kortum, B, Kulkarni, N, Kwan, E, Lange, T, Larmann, M, Larter, T, Laturkar, K, LaVere, M, Laxdal, RE, LeTourneau, J, Li, Z-Y, Lidia, S, Machicoane, G, Magsig, C, Manwiller, P, Marti, F, Maruta, T, Metzgar, E, Miller, S, Momozaki, Y, Mugerian, M, Morris, D, Nesterenko, I, Nguyen, C, Ostroumov, P, Patil, M, Plastun, A, Popielarski, L, Portillo, M, Powers, A, Priller, J, Rao, X, Reaume, M, Rodriguez, S, Rogers, S, Saito, K, Sherrill, BM, Smith, MK, Song, J, Steiner, M, Stolz, A, Tarasov, O, Tousignant, B, Walker, R, Wang, X, Wenstrom, J, West, G, Witgen, K, Wright, M, Xu, T, Yamazaki, Y, Zhang, T, Zhao, Q, Zhao, S, Hurh, P, Prestemon, S, and Shen, T

Subjects
Nuclear and Plasma Physics, Engineering, Synchrotrons and Accelerators, Physical Sciences, Nuclear & Particles Physics, Physical sciences
Abstract

The Facility for Rare Isotope Beams (FRIB) began operation with 1 kW beam power for scientific users in May 2022 upon completion of 8 years of project construction. The ramp-up to the ultimate beam power of 400 kW, planned over a 6-year period, will enable the facility to reach its full potential for scientific discovery in isotope science and applications. In December 2023, a record-high beam power of 10.4 kW uranium was delivered to the target. Technological developments and accelerator improvements are being made over the entire facility and are key to completion of the power ramp-up. Major technological developments entail the phased deployment of high-power beam-intercepting systems, including the charge strippers, the charge selection systems, the production target, and the beam dump, along with support systems, including non-conventional utilities (NCU) and remote handling facilities. Major accelerator improvements include renovations to aging legacy systems associated with experimental beam lines and system automation for improved operational efficiency and better machine availability. Experience must be gained to safely handle the increased radiological impacts associated with high beam power; extensive machine studies and advanced beam tuning procedures are needed to minimize uncontrolled beam losses for the desired operating conditions. This paper discusses the technological developments and accelerator improvements with emphasis on major R&D efforts.

Published
2024

3. Key directions for research and development of superconducting radio frequency cavities

Author

Belomestnykh, S., Posen, S., Bafia, D., Balachandran, S., Bertucci, M., Burrill, A., Cano, A., Checchin, M., Ciovati, G., Cooley, L. D., Semione, G. Dalla Lana, Delayen, J., Eremeev, G., Furuta, F., Gerigk, F., Giaccone, B., Gonnella, D., Grassellino, A., Gurevich, A., Hillert, W., Iavarone, M., Knobloch, J., Kubo, T., Kwok, W. K., Laxdal, R., Lee, P. J., Liepe, M., Martinello, M., Melnychuk, O. S., Nassiri, A., Netepenko, A., Padamsee, H., Pagani, C., Paparella, R., Pudasaini, U., Reece, C. E., Reschke, D., Romanenko, A., Ross, M., Saito, K., Sauls, J., Seidman, D. N., Solyak, N., Sung, Z., Umemori, K., Valente-Feliciano, A. -M., Delsolaro, W. Venturini, Walker, N., Weise, H., Welp, U., Wenskat, M., Wu, G., Xi, X. X., Yakovlev, V., Yamamoto, A., and Zasadzinski, J.

Subjects
Physics - Accelerator Physics
Abstract

Radio frequency superconductivity is a cornerstone technology for many future HEP particle accelerators and experiments from colliders to proton drivers for neutrino facilities to searches for dark matter. While the performance of superconducting RF (SRF) cavities has improved significantly over the last decades, and the SRF technology has enabled new applications, the proposed HEP facilities and experiments pose new challenges. To address these challenges, the field continues to generate new ideas and there seems to be a vast room for improvements. In this paper we discuss the key research directions that are aligned with and address the future HEP needs., Comment: contribution to Snowmass 2021

Published
2022

4. Impact of Hospital Closure on Patients with Communicable and Non-Communicable Diseases During the COVID-19 Pandemic in Uganda: A Cross-Sectional and Mixed-Methods Study

Author

Komasawa M, Aung MN, Nsereko C, Ssekitoleko R, Isono M, Saito K, Nantume J, Shirayama Y, Chandani S, and Yuasa M

Subjects
lockdown, public health and social measures, health service disruption, tuberculosis, hiv, mental illness, Public aspects of medicine, RA1-1270
Abstract

Makiko Komasawa,1,2 Myo Nyein Aung,2 Christopher Nsereko,3 Robert Ssekitoleko,4 Mitsuo Isono,5 Kiyoko Saito,1 Jesca Nantume,4 Yoshihisa Shirayama,2 Shrestha Chandani,1 Motoyuki Yuasa2 1Ogata Sadako Research Institute for Peace and Development, Japan International Cooperation Agency, Tokyo, Japan; 2Department of Global Health Research, Graduate School of Medicine, Juntendo University, Tokyo, Japan; 3Department of Internal Medicine, Entebbe Regional Referral Hospital, Entebbe, Uganda; 4College of Health Sciences, Makerere University, Kampala, Uganda; 5Department of Human Development, Japan International Cooperation Agency, Tokyo, JapanCorrespondence: Makiko Komasawa, Ogata Sadako Research Institute for Peace and Development, Japan International Cooperation Agency, 10-5, Ichigaya Honmura-cho, Shinjuku-ku, Tokyo, 162-8433, Japan, Tel +81-3-3269-2911, Fax +81-3-3269-2054, Email mkomasa@juntendo.ac.jpBackground: The COVID-19 pandemic and its measures have had a profound impact on universal access to health services. We investigated the impact of the closure of the Entebbe Regional Referral Hospital (ERRH) for two years on the accessibility to necessary healthcare among non-COVID-19 patients.Methods: This mixed-methods study focused on ERRH patients with tuberculosis (TB), human immunodeficiency virus (HIV), diabetes/hypertension, and mental illness. A quantitative study used a structured-questionnaire with a primary outcome measure to assess the discontinuation of healthcare accessibility. A qualitative study with a focus group discussion (FGD) was conducted on eight patients.Results: Of the 202 quantitative survey participants, 17.8% discontinued necessary healthcare due to the ERRH closure, and the discontinuation rates differed by disease: 48.1% of TB patients, 16.0% of HIV patients, 7.8% of diabetes/hypertension patients, and 4.0% of mental health patients (P < 0.001). Almost 90% of the patients reported a worsened health condition, regardless of the disease. Multivariable logistic regression analysis showed that patients with diabetes/hypertension (adjusted odds ratio [AOR], 12.69; 95% confidence interval [CI], 2.57– 62.52) and HIV (AOR, 7.52; 95% CI, 1.37– 41.27) were more likely to discontinue healthcare than those with mental illness. The factors associated with discontinued healthcare included age ≥ 50 years vs ≤ 30 years (AOR, 4.88; 95% CI, 1.07– 22.34), and high transportation cost vs low cost (AOR, 3.15; 95% CI, 1.13– 8.75). The FGD also identified difficulties in obtaining medication, especially for TB, even though ERRH provided the outreach services.Conclusion: Our study revealed that the ERRH closure and lockdowns had an overall profound negative impact on access to healthcare and health conditions. Younger patients and those with TB were the most affected patients. This study provides practical suggestions from the field for policy makers to strengthen universal health access during health crises in Uganda and other sub-Saharan countries.Plain Language Summary: This study investigated the impact of service disruption in a tertiary hospital (ERRH) that was converted to a COVID-19-dedicated hospital for two years in Uganda. This mixed-methods study focused on the ERRH patients with tuberculosis (TB), human immunodeficiency virus (HIV), diabetes, hypertension, and mental illness. A quantitative study used a structured questionnaire with the primary outcome measure being the discontinuation of healthcare provision. A qualitative study with a focus group discussion (FGD) was conducted on eight patients. Of the 202 quantitative survey participants, 17.8% discontinued necessary healthcare due to ERRH closure, and the discontinuation rates differed by disease: 48.1% of tuberculosis patients, 16.0% of HIV patients, 7.8% of diabetes/hypertension patients, and 4.0% of mental health patients (P < 0.001). Almost 90% of the patients reported worsening health conditions. The factors associated with discontinued healthcare included age ≥ 50 years vs ≤ 30 years (AOR, 4.88; 95% CI, 1.07-22.34), and high transportation costs vs low cost (AOR, 3.15; 95% CI, 1.13-8.75). The FGD also identified difficulties in obtaining medication, especially for TB, even though the ERRH provided outreach services. Our study revealed that ERRH closures and lockdowns had profound negative impacts on access to health care and health conditions. Younger patients and those with TB were the most affected patients. This study provides suggestions from the field for policy makers to strengthen universal health access during health crises in Uganda and other sub-Saharan countries.Keywords: lockdown, public health and social measures, health service disruption, tuberculosis, HIV, mental illness

Published
2023

6. Intrinsic coercivity induced by valence fluctuations in $4f$-$3d$ intermetallic magnets

Author

Shishido, H., Ueno, T., Saito, K., Sawada, M., and Matsumoto, M.

Subjects
Condensed Matter - Strongly Correlated Electrons, Physics - Applied Physics
Abstract

Temperature dependence of magnetization curves of well homogenized samples of Ce(Co$_{1-x}$Cu$_{x}$)$_5$ ($0\le x \le 0.7$), a family of representative $4f$-$3d$ intermetallic magnets found in rare-earth permanent magnets, is measured. A remarkable enhancement of intrinsic coercivity is observed with $x=0.3$ and $x=0.4$, persisting to higher temperatures. This experimental observation is theoretically attributed to an effect of electronic correlation among $4f$-electrons. That is, an intrinsic pinning happens originating in an anomalously enhanced magnetic anisotropy energy contributed by an order of magnitude stronger charge-transfer process between $4f$-electrons and $3d$-electrons, than the conventional crystal field effects. It is demonstrated that the $4f$-$3d$ charge-transfer process depends on the direction of magnetization in the middle of a crossover of the valence state of Ce between CeCu$_5$ with robust Ce$^{3+}$ and CeCo$_5$ with the mixed valence state., Comment: 7 pages, 4 figures

Published
2021

7. Observations of the Origin of Downward Terrestrial Gamma-Ray Flashes

Author

Belz, J. W., Krehbiel, P. R., Remington, J., Stanley, M. A., Abbasi, R. U., LeVon, R., Rison, W., Rodeheffer, D., Collaboration, the Telescope Array Scientific, Abu-Zayyad, T., Allen, M., Barcikowski, E., Bergman, D. R., Blake, S. A., Byrne, M., Cady, R., Cheon, B. G., Chikawa, M., di Matteo, A., Fujii, T., Fujita, K., Fujiwara, R., Fukushima, M., Furlich, G., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inadomi, T., Inoue, N., Ishii, T., Ito, H., Ivanov, D., Iwakura, H., Jeong, H. M., Jeong, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kasami, S., Kawai, H., Kawakami, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Matsumiya, H., Matthews, J. N., Matuyama, T., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagataki, S., Nakai, K., Nakamura, R., Nakamura, T., Nakamura, Y., Nonaka, T., Oda, H., Ogio, S., Ohnishi, M., Ohoka, H., Oku, Y., Okuda, T., Omura, Y., Ono, M., Oshima, A., Ozawa, S., Park, I. H., Potts, M., Pshirkov, M. S., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sako, T., Sakurai, N., Sano, K., Seki, T., Sekino, K., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Sone, N., Stokes, B. T., Stroman, T. A., Takagi, Y., Takahashi, Y., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, K., Tanaka, M., Tanoue, Y., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Uchihori, Y., Udo, S., Uehama, T., Urban, F., Wallace, M., Wong, T., Yamamoto, M., Yamaoka, H., Yamazaki, K., Yashiro, K., Yosei, M., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Physics - Atmospheric and Oceanic Physics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

In this paper we report the first close, high-resolution observations of downward-directed terrestrial gamma-ray flashes (TGFs) detected by the large-area Telescope Array cosmic ray observatory, obtained in conjunction with broadband VHF interferometer and fast electric field change measurements of the parent discharge. The results show that the TGFs occur during strong initial breakdown pulses (IBPs) in the first few milliseconds of negative cloud-to-ground and low-altitude intracloud flashes, and that the IBPs are produced by a newly-identified streamer-based discharge process called fast negative breakdown. The observations indicate the relativistic runaway electron avalanches (RREAs) responsible for producing the TGFs are initiated by embedded spark-like transient conducting events (TCEs) within the fast streamer system, and potentially also by individual fast streamers themselves. The TCEs are inferred to be the cause of impulsive sub-pulses that are characteristic features of classic IBP sferics. Additional development of the avalanches would be facilitated by the enhanced electric field ahead of the advancing front of the fast negative breakdown. In addition to showing the nature of IBPs and their enigmatic sub-pulses, the observations also provide a possible explanation for the unsolved question of how the streamer to leader transition occurs during the initial negative breakdown, namely as a result of strong currents flowing in the final stage of successive IBPs, extending backward through both the IBP itself and the negative streamer breakdown preceding the IBP., Comment: Typo fixed and reference added. Manuscript is 36 pages. Supplemental Information is 42 pages. This paper is to be published in the Journal of Geophysical Research: Atmospheres. Online data repository: Open Science Framework DOI: 10.17605/OSF.IO/Z3XDA

Published
2020
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9. Search for Ultra-High-Energy Neutrinos with the Telescope Array Surface Detector

Author

Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., di Matteo, A., Fujii, T., Fujisue, K., Fujita, K., Fujiwara, R., Fukushima, M., Furlich, G., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakai, K., Nakamura, R., Nakamura, T., Nonaka, T., Oda, H., Ogio, S., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Remington, J., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sako, T., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Tanoue, Y., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yada, K., Yamamoto, M., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We present an upper limit on the flux of ultra-high-energy down-going neutrinos for $E > 10^{18}\ \mbox{eV}$ derived with the nine years of data collected by the Telescope Array surface detector (05-11-2008 -- 05-10-2017). The method is based on the multivariate analysis technique, so-called Boosted Decision Trees (BDT). Proton-neutrino classifier is built upon 16 observables related to both the properties of the shower front and the lateral distribution function., Comment: 10 pages, 4 figures, accepted to JETP

Published
2019
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10. Nitrogen Contamination Causes High Field Q-Slope (HFQS) in Buffered Chemical Polished SRF Cavities

Author

Luo, D., Saito, K., and Shanab, S.

Subjects
Physics - Accelerator Physics
Abstract

Buffered Chemical Polishing (BCP) was the most conventional polishing method for superconducting radio frequency (SRF) Niobium (Nb) cavity surface preparation before the discovery of Electropolishing (EP), which is superior to BCP in high gradient performance. The High Field Q-slope (HFQS) is perfectly eliminated by taking the low temperature bake (LTB) post EP, which guarantees high gradient performance in EP'ed cavities. The mechanism of the HFQS is well understood for EP'ed cavities. On the other hand, there is no common consensus on the HFQS with BCP, since even BCP with LTB does not always resolve the HFQS. BCP is much easier to apply and still an important preparation technology for very complicated SRF structures like low beta cavities. Therefore, overcoming the issue of HFQS with BCP is highly beneficial to the SRF community. This paper mines a large number of available data sets on BCP'ed cavity performance with fine grain, large grain, and even single crystal niobium materials under different experimental settings. We found that all existing explanations for HFQS with BCP are inconsistent with some experimental results, and propounded nitrogen contamination as a new model. We checked that nitrogen contamination agrees with all existing data and nicely explains unresolved phenomena. Combining these evidence, we deduce that nitrogen contamination is the cause of HFQS in BCP.

Published
2019

11. Search for point sources of ultra-high energy photons with the Telescope Array surface detector

Author

Telescope Array Collaboration, Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., diMatteo, A., Fujii, T., Fujita, K., Fujiwara, R., Fukushima, M., Furlich, G., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagataki, S., Nakai, K., Nakamura, R., Nakamura, T., Nonaka, T., Oda, H., Ogio, S., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Remington, J., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sako, T., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Tanoue, Y., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yada, K., Yamamoto, M., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The surface detector (SD) of the Telescope Array (TA) experiment allows one to indirectly detect photons with energies of order $10^{18}$ eV and higher and to separate photons from the cosmic-ray background. In this paper we present the results of a blind search for point sources of ultra-high energy (UHE) photons in the Northern sky using the TA SD data. The photon-induced extensive air showers (EAS) are separated from the hadron-induced EAS background by means of a multivariate classifier based upon 16 parameters that characterize the air shower events. No significant evidence for the photon point sources is found. The upper limits are set on the flux of photons from each particular direction in the sky within the TA field of view, according to the experiment's angular resolution for photons. Average 95% C.L. upper limits for the point-source flux of photons with energies greater than $10^{18}$, $10^{18.5}$, $10^{19}$, $10^{19.5}$ and $10^{20}$ eV are $0.094$, $0.029$, $0.010$, $0.0073$ and $0.0058$ km$^{-2}$yr$^{-1}$ respectively. For the energies higher than $10^{18.5}$ eV, the photon point-source limits are set for the first time. Numerical results for each given direction in each energy range are provided as a supplement to this paper., Comment: accepted to MNRAS, 11 pages, 4 figures, 2 tables; results in text-file format are supplemented to paper source

Published
2019
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13. Early Bactericidal Activity Trial of Nitazoxanide for Pulmonary Tuberculosis.

Author

Walsh, KF, McAulay, K, Lee, MH, Vilbrun, SC, Mathurin, L, Jean Francois, D, Zimmerman, M, Kaya, F, Zhang, N, Saito, K, Ocheretina, O, Savic, R, Dartois, V, Johnson, WD, Pape, JW, Nathan, C, and Fitzgerald, DW

Subjects
Orphan Drug, Tuberculosis, Lung, Clinical Research, Infectious Diseases, Clinical Trials and Supportive Activities, HIV/AIDS, Rare Diseases, Evaluation of treatments and therapeutic interventions, 6.1 Pharmaceuticals, Infection, Good Health and Well Being, Adult, Antitubercular Agents, Female, Haiti, Humans, Male, Microbial Sensitivity Tests, Mycobacterium tuberculosis, Nitro Compounds, Sputum, Thiazoles, Tuberculosis, Pulmonary, Young Adult, tuberculosis, nitazoxanide, bactericidal activity, Microbiology, Medical Microbiology, Pharmacology and Pharmaceutical Sciences
Abstract

This study was conducted in treatment-naive adults with drug-susceptible pulmonary tuberculosis in Port-au-Prince, Haiti, to assess the safety, bactericidal activity, and pharmacokinetics of nitazoxanide (NTZ). This was a prospective phase II clinical trial in 30 adults with pulmonary tuberculosis. Twenty participants received 1 g of NTZ orally twice daily for 14 days. A control group of 10 participants received standard therapy over 14 days. The primary outcome was the change in time to culture positivity (TTP) in an automated liquid culture system. The most common adverse events seen in the NTZ group were gastrointestinal complaints and headache. The mean change in TTP in sputum over 14 days in the NTZ group was 3.2 h ± 22.6 h and was not statistically significant (P = 0.56). The mean change in TTP in the standard therapy group was significantly increased, at 134 h ± 45.2 h (P

Published
2020

14. Constraints on the diffuse photon flux with energies above $10^{18}$ eV using the surface detector of the Telescope Array experiment

Author

Telescope Array Collaboration, Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., di Matteo, A., Fujii, T., Fujita, K., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Oda, H., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Piskunov, M. S., Pshirkov, M. S., Remington, J., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

We present the results of the search for ultra-high-energy photons with nine years of data from the Telescope Array surface detector. A multivariate classifier is built upon 16 reconstructed parameters of the extensive air shower. These parameters are related to the curvature and the width of the shower front, the steepness of the lateral distribution function, and the timing parameters of the waveforms sensitive to the shower muon content. A total number of two photon candidates found in the search is fully compatible with the expected background. The $95\%\,$CL limits on the diffuse flux of the photons with energies greater than $10^{18.0}$, $10^{18.5}$, $10^{19.0}$, $10^{19.5}$ and $10^{20.0}$ eV are set at the level of $0.067$, $0.012$, $0.0036$, $0.0013$, $0.0013~\mbox{km}^{-2}\mbox{yr}^{-1}\mbox{sr}^{-1}$ correspondingly., Comment: 7 pages, 2 figures

Published
2018
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15. Testing a reported correlation between arrival directions of ultrahigh-energy cosmic rays and a flux pattern from nearby starburst galaxies using Telescope Array data

Author

Telescope Array Collaboration, Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., di Matteo, A., Fujii, T., Fujita, K., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Oda, H., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Remington, J., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Pierre Auger Collaboration (Auger) recently reported a correlation between the arrival directions of cosmic rays with energies above 39 EeV and the flux pattern of 23 nearby starburst galaxies (SBGs). In this Letter, we tested the same hypothesis using cosmic rays detected by the Telescope Array experiment (TA) in the 9-year period from May 2008 to May 2017. Unlike the Auger analysis, we did not optimize the parameter values but kept them fixed to the best-fit values found by Auger, namely 9.7% for the anisotropic fraction of cosmic rays assumed to originate from the SBGs in the list and 12.9{\deg} for the angular scale of the correlations. The energy threshold we adopted is 43 EeV, corresponding to 39 EeV in Auger when taking into account the energy-scale difference between two experiments. We find that the TA data is compatible with isotropy to within 1.1{\sigma} and with the Auger result to within 1.4{\sigma}, meaning that it is not capable to discriminate between these two hypotheses., Comment: More accurate title, fixed an inconsistency in the declination range used, with a few figures slightly changing as a result, other minor revisions

Published
2018
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16. Mass composition of ultra-high-energy cosmic rays with the Telescope Array Surface Detector Data

Author

Telescope Array Collaboration, Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., di Matteo, A., Fujii, T., Fujita, K., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Oda, H., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Piskunov, M. S., Pshirkov, M. S., Remington, J., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The results on ultra-high-energy cosmic rays (UHECR) mass composition obtained with the Telescope Array surface detector are presented. The analysis employs the boosted decision tree (BDT) multivariate analysis built upon 14 observables related to both the properties of the shower front and the lateral distribution function. The multivariate classifier is trained with Monte-Carlo sets of events induced by the primary protons and iron. An average atomic mass of UHECR is presented for energies $10^{18.0}-10^{20.0}\ \mbox{eV}$. The average atomic mass of primary particles shows no significant energy dependence and corresponds to $\langle \ln A \rangle = 2.0 \pm 0.1 (stat.) \pm 0.44 (syst.)$. The result is compared to the mass composition obtained by the Telescope Array with $\mbox{X}_{\mbox{max}}$ technique along with the results of other experiments. Possible systematic errors of the method are discussed., Comment: 11 pages, 9 figures

Published
2018
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17. Study of muons from ultra-high energy cosmic ray air showers measured with the Telescope Array experiment

Author

Telescope Array Collaboration, Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Di Matteo, A., Fujii, T., Fujita, K., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S. M., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Oda, H., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Remington, J., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

One of the uncertainties in interpretation of ultra-high energy cosmic ray (UHECR) data comes from the hadronic interaction models used for air shower Monte Carlo (MC) simulations. The number of muons observed at the ground from UHECR-induced air showers is expected to depend upon the hadronic interaction model. One may therefore test the hadronic interaction models by comparing the measured number of muons with the MC prediction. In this paper, we present the results of studies of muon densities in UHE extensive air showers obtained by analyzing the signal of surface detector stations which should have high $\it{muon \, purity}$. The muon purity of a station will depend on both the inclination of the shower and the relative position of the station. In 7 years' data from the Telescope Array experiment, we find that the number of particles observed for signals with an expected muon purity of $\sim$65% at a lateral distance of 2000 m from the shower core is $1.72 \pm 0.10{\rm (stat.)} \pm 0.37 {\rm (syst.)}$ times larger than the MC prediction value using the QGSJET II-03 model for proton-induced showers. A similar effect is also seen in comparisons with other hadronic models such as QGSJET II-04, which shows a $1.67 \pm 0.10 \pm 0.36$ excess. We also studied the dependence of these excesses on lateral distances and found a slower decrease of the lateral distribution of muons in the data as compared to the MC, causing larger discrepancy at larger lateral distances.

Published
2018
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18. The Cosmic-Ray Energy Spectrum between 2 PeV and 2 EeV Observed with the TALE detector in monocular mode

Author

Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Di Matteo, A., Fujii, T., Fujita, K., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S. M., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Nozato, A., Oda, H., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We report on a measurement of the cosmic ray energy spectrum by the Telescope Array Low-Energy Extension (TALE) air fluorescence detector. The TALE air fluorescence detector is also sensitive to the Cherenkov light produced by shower particles. Low energy cosmic rays, in the PeV energy range, are detectable by TALE as "Cherenkov Events". Using these events, we measure the energy spectrum from a low energy of $\sim 2$ PeV to an energy greater than 100 PeV. Above 100 PeV TALE can detect cosmic rays using air fluorescence. This allows for the extension of the measurement to energies greater than a few EeV. In this paper, we will describe the detector, explain the technique, and present results from a measurement of the spectrum using $\sim 1000$ hours of observation. The observed spectrum shows a clear steepening near $10^{17.1}$ eV, along with an ankle-like structure at $10^{16.2}$ eV. These features present important constraints on galactic cosmic rays origin and propagation models. The feature at $10^{17.1}$ eV may also mark the end of the galactic cosmic rays flux and the start of the transition to extra-galactic sources., Comment: 26 pages, 24 figures, submitted to ApJ

Published
2018
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19. Evidence of Intermediate-Scale Energy Spectrum Anisotropy of Cosmic Rays E$\geq$10$^{19.2}$ eV with the Telescope Array Surface Detector

Author

Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Di Matteo, A., Fujii, T., Fujita, K., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, H. M., Jeong, S. M., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lee, K. H., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Nozato, A., Oda, H., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

An intermediate-scale energy spectrum anisotropy has been found in the arrival directions of ultra-high energy cosmic rays of energies above $10^{19.2}$ eV in the northern hemisphere, using 7 years of data from the Telescope Array surface detector. A relative energy distribution test is done comparing events inside oversampled spherical caps of equal exposure, to those outside, using the Poisson likelihood ratio. The center of maximum significance is at $9^h$$16^m$, $45^{\circ}$. and has a deficit of events with energies $10^{19.2}$$\leq$$E$$<$$10^{19.75}$ eV and an excess for $E$$\geq$$10^{19.75}$ eV. The post-trial probability of this energy anisotropy, appearing by chance anywhere on an isotropic sky, is found by Monte Carlo simulation to be $9$$\times$$10^{-5}$ ($3.74$$\sigma_{global}$).

Published
2018
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20. Depth of Ultra High Energy Cosmic Ray Induced Air Shower Maxima Measured by the Telescope Array Black Rock and Long Ridge FADC Fluorescence Detectors and Surface Array in Hybrid Mode

Author

Telescope Array Collaboration, Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Fujii, T., Fujita, K., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, M., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jeong, S. M., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lubsandorzhiev, B., Lundquist, J. P., Machida, M., Martens, K., Matsuyama, T., Matthews, J. N., Mayta, R., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Nozato, A., Oda, H., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Okuda, T., Omura, Y., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Sahara, R., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takagi, Y., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Telescope Array observatory utilizes fluorescence detectors and surface detectors to observe air showers produced by ultra high energy cosmic rays in the Earth's atmosphere. Cosmic ray events observed in this way are termed hybrid data. The depth of air shower maximum is related to the mass of the primary particle that generates the shower. This paper reports on shower maxima data collected over 8.5 years using the Black Rock Mesa and Long Ridge fluorescence detectors in conjunction with the array of surface detectors. We compare the means and standard deviations of the observed $X_{\mathrm{max}}$ distributions with Monte Carlo $X_{\mathrm{max}}$ distributions of unmixed protons, helium, nitrogen, and iron, all generated using the QGSJet~II-04 hadronic model. We also perform an unbinned maximum likelihood test of the observed data, which is subjected to variable systematic shifting of the data $X_{\mathrm{max}}$ distributions to allow us to test the full distributions, and compare them to the Monte Carlo to see which elements are not compatible with the observed data. For all energy bins, QGSJet~II-04 protons are found to be compatible with Telescope Array hybrid data at the 95% confidence level after some systematic $X_{\mathrm{max}}$ shifting of the data. Three other QGSJet~II-04 elements are found to be compatible using the same test procedure in an energy range limited to the highest energies where data statistics are sparse., Comment: 39 pages, 18 figures, 5 tables, published in The Astrophysical Journal. This is a peer-reviewed, un-copyedited version of an article published in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.3847/1538-4357/aabad7

Published
2018
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21. Advances of the FRIB project

Author

Wei, J, Ao, H, Beher, S, Bultman, N, Casagrande, F, Cogan, S, Compton, C, Curtin, J, Dalesio, L, Davidson, K, Dixon, K, Facco, A, Ganni, V, Ganshyn, A, Gibson, P, Glasmacher, T, Hao, Y, Hodges, L, Holland, K, Hosoyama, K, Hseuh, H-C, Hussain, A, Ikegami, M, Jones, S, Kanemura, T, Kelly, M, Knudsen, P, Laxdal, RE, LeTourneau, J, Lidia, S, Machicoane, G, Marti, F, Miller, S, Momozaki, Y, Morris, D, Ostroumov, P, Popielarski, J, Popielarski, L, Prestemon, S, Priller, J, Ren, H, Russo, T, Saito, K, Stanley, S, Wiseman, M, Xu, T, and Yamazaki, Y

Subjects
Nuclear and Plasma Physics, Synchrotrons and Accelerators, Physical Sciences, Affordable and Clean Energy, Mathematical Sciences, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract

The Facility for Rare Isotope Beams (FRIB) Project has entered the phase of beam commissioning starting from the room-temperature front end and the superconducting linac segment of first 15 cryomodules. With the newly commissioned helium refrigeration system supplying 4.5K liquid helium to the quarter-wave resonators and solenoids, the FRIB accelerator team achieved the sectional key performance parameters as designed ahead of schedule accelerating heavy ion beams above 20MeV/u energy. Thus, FRIB accelerator becomes world's highest-energy heavy ion linear accelerator. We also validated machine protection and personnel protection systems that will be crucial to the next phase of commissioning. FRIB is on track towards a national user facility at the power frontier with a beam power two orders of magnitude higher than operating heavy-ion facilities. This paper summarizes the status of accelerator design, technology development, construction, commissioning as well as path to operations and upgrades.

Published
2019

22. Search for Anisotropy in the Ultra High Energy Cosmic Ray Spectrum using the Telescope Array Surface Detector

Author

Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Fujii, T., Fukushima, M., Goto, T., Hanlon, W., Hayashi, Y., Hayashi, M., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kuznetsov, M., Kwon, Y. J., Lan, J., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuda, T., Matsuyama, T., Matthews, J. N., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nonaka, T., Nozato, A., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Oki, K., Okuda, T., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Sekino, K., Shah, P. D., Shibata, T., Shibata, F., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, M., Tanaka, K., Tanaka, H., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zhezher, Y., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

The Telescope Array (TA) experiment is located in the western desert of Utah, USA, and observes ultra high energy cosmic rays (UHECRs) in the Northern hemisphere. At the highest energies, $E>10$~EeV, the shape of cosmic ray energy spectrum may carry an imprint of the source density distribution along the line of sight different in different directions of the sky. In this study, we search for such directional variations in the shape of the energy spectrum using events observed with the Telescope Array's surface detector. We divide the TA field of view into two nearly equal-exposure regions: the "on-source" region which we define as $\pm 30^\circ$ of the supergalactic plane containing mostly nearby structures, and the complementary "off-source" region where the sources are further away on average. We compare the UHECR spectra in these regions by fitting them to the broken power law and comparing the resulting parameters. We find that the off-source spectrum has an earlier break at highest energies. The chance probability to obtain such or larger difference in statistically equivalent distributions is estimated as $6.2\pm1.1\times10^{-4}$ ($3.2\sigma$) by a Monte-Carlo simulation. The observed difference in spectra is in a reasonable quantitative agreement with a simplified model that assumes that the UHECR sources trace the galaxy distribution from the 2MRS catalogue, primary particles are protons and the magnetic deflections can be neglected., Comment: 17 pages 6 figures, submitted to Physical Review Letters, (31.May.2017)

Published
2017

23. Nonlinear transport associated with spin-density-wave dynamics in Ca$_3$Co$_{4}$O$_9$

Author

Murashige, N., Takei, F., Saito, K., and Okazaki, R.

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

We have carried out the transient nonlinear transport measurements on the layered cobalt oxide Ca$_3$Co$_{4}$O$_9$, in which a spin density wave (SDW) transition is proposed at $T_{\rm SDW} \simeq 30$ K. We find that, below $T_{\rm SDW}$, the electrical conductivity systematically varies with both the applied current and the time, indicating a close relationship between the observed nonlinear conduction and the SDW order in this material. The time dependence of the conductivity is well analyzed by considering the dynamics of SDW which involves a low-field deformation and a sliding motion above a threshold field. We also measure the transport properties of the isovalent Sr-substituted systems to examine an impurity effect on the nonlinear response, and discuss the obtained threshold fields in terms of thermal fluctuations of the SDW order parameter., Comment: 6 pages, 7 figures, to be published in Phys. Rev. B

Published
2017
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24. Gamma-ray Showers Observed at Ground Level in Coincidence With Downward Lightning Leaders

Author

Abbasi, R. U., Abu-Zayyad, T., Allen, M., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Byrne, M., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Fujii, T., Fukushima, M., Furlich, G., Goto, T., Hanlon, W., Hayashi, Y., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ito, H., Ivanov, D., Jeong, S., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S. S., Krehbiel, P. R., Kuzmin, V., Kwon, Y. J., Lan, J., LeVon, R., Lundquist, J. P., Machida, K., Martens, K., Matuyama, T., Matthews, J. N., Minamino, M., Mukai, K., Myers, I., Nagataki, S., Nakamura, R., Nakamura, T., Nonaka, T., Ogio, S., Ohnishi, M., Ohoka, H., Oki, K., Okuda, T., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Remington, J., Rison, W., Rodeheffer, D., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Saito, K., Sakaki, N., Sakurai, N., Seki, T., Sekino, K., Shah, P. D., Shibata, F., Shibata, T., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Springer, R. W., Stokes, B. T., Stroman, T. A., Takai, H., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, H., Tanaka, K., Tanaka, M., Thomas, R. J., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Uchihori, Y., Udo, S., Urban, F., Vasiloff, G., Wong, T., Yamamoto, M., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., and Zundel, Z.

Subjects
Physics - Atmospheric and Oceanic Physics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

Bursts of gamma ray showers have been observed in coincidence with downward propagating negative leaders in lightning flashes by the Telescope Array Surface Detector (TASD). The TASD is a 700~square kilometer cosmic ray observatory located in southwestern Utah, U.S.A. In data collected between 2014 and 2016, correlated observations showing the structure and temporal development of three shower-producing flashes were obtained with a 3D lightning mapping array, and electric field change measurements were obtained for an additional seven flashes, in both cases co-located with the TASD. National Lightning Detection Network (NLDN) information was also used throughout. The showers arrived in a sequence of 2--5 short-duration ($\le$10~$\mu$s) bursts over time intervals of several hundred microseconds, and originated at an altitude of $\simeq$3--5 kilometers above ground level during the first 1--2 ms of downward negative leader breakdown at the beginning of cloud-to-ground lightning flashes. The shower footprints, associated waveforms and the effect of atmospheric propagation indicate that the showers consist primarily of downward-beamed gamma radiation. This has been supported by GEANT simulation studies, which indicate primary source fluxes of $\simeq$$10^{12}$--$10^{14}$ photons for $16^{\circ}$ half-angle beams. We conclude that the showers are terrestrial gamma-ray flashes (TGFs), similar to those observed by satellites, but that the ground-based observations are more representative of the temporal source activity and are also more sensitive than satellite observations, which detect only the most powerful TGFs.

Published
2017
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25. Towards a Unified Model of Neutrino-Nucleus Reactions for Neutrino Oscillation Experiments

Author

Nakamura, S. X., Kamano, H., Hayato, Y., Hirai, M., Horiuchi, W., Kumano, S., Murata, T., Saito, K., Sakuda, M., Sato, T., and Suzuki, Y.

Subjects
Nuclear Theory, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

A precise description of neutrino-nucleus reactions will play a key role in addressing fundamental questions such as the leptonic CP violation and the neutrino mass hierarchy through analyzing data from next-generation neutrino oscillation experiments. The neutrino energy relevant to the neutrino-nucleus reactions spans a broad range and, accordingly, the dominant reaction mechanism varies across the energy region from quasi-elastic scattering through nucleon resonance excitations to deep inelastic scattering. This corresponds to transitions of the effective degree of freedom for theoretical description from nucleons through meson-baryon to quarks. The main purpose of this review is to report our recent efforts towards a unified description of the neutrino-nucleus reactions over the wide energy range; recent overall progress in the field is also sketched. Starting with an overview of the current status of neutrino-nucleus scattering experiments, we formulate the cross section to be commonly used for the reactions over all the energy regions. A description of the neutrino-nucleon reactions follows and, in particular, a dynamical coupled-channels model for meson productions in and beyond the $\Delta$(1232) region is discussed in detail. We then discuss the neutrino-nucleus reactions, putting emphasis on our theoretical approaches. We start the discussion with electroweak processes in few-nucleon systems studied with the correlated Gaussian method. Then we describe quasi-elastic scattering with nuclear spectral functions, and meson productions with a $\Delta$-hole model. Nuclear modifications of the parton distribution functions determined through a global analysis are also discussed. Finally, we discuss issues to be addressed for future developments., Comment: 68 pages, 33 figures; (v2) reference added, author name in metadata corrected; (v3) Discussion extended in Sec. I and IV, Fig. 10 added to compare with a previous result on two-pion productions, Table I extended to include a comparison with a recent T2K result on coherent pion production

Published
2016
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26. Search for EeV Protons of Galactic Origin

Author

Abbasi, R. U., Abe, M., Abu-Zayyad, T., Allen, M., Azuma, R., Barcikowski, E., Belz, J. W., Bergman, D. R., Blake, S. A., Cady, R., Cheon, B. G., Chiba, J., Chikawa, M., Fujii, T., Fukushima, M., Goto, T., Hanlon, W., Hayashi, Y., Hayashi, M., Hayashida, N., Hibino, K., Honda, K., Ikeda, D., Inoue, N., Ishii, T., Ishimori, R., Ito, H., Ivanov, D., Jui, C. C. H., Kadota, K., Kakimoto, F., Kalashev, O., Kasahara, K., Kawai, H., Kawakami, S., Kawana, S., Kawata, K., Kido, E., Kim, H. B., Kim, J. H., Kishigami, S., Kitamura, S., Kitamura, Y., Kuzmin, V., Kwon, Y. J., Lan, J., Lubsandorzhiev, B., Lundquist, J. P., Machida, K., Martens, K., Matsuda, T., Matsuyama, T., Matthews, J. N., Minamino, M., Mukai, K., Myers, I., Nagasawa, K., Nagataki, S., Nakamura, T., Nonaka, T., Nozato, A., Ogio, S., Ogura, J., Ohnishi, M., Ohoka, H., Oki, K., Okuda, T., Ono, M., Onogi, R., Oshima, A., Ozawa, S., Park, I. H., Pshirkov, M. S., Rodriguez, D. C., Rubtsov, G., Ryu, D., Sagawa, H., Saito, K., Saito, Y., Sakaki, N., Sakurai, N., Scott, L. M., Sekino, K., Shah, P. D., Shibata, T., Shibata, F., Shimodaira, H., Shin, B. K., Shin, H. S., Smith, J. D., Sokolsky, P., Stokes, B. T., Stratton, S. R., Stroman, T. A., Suzawa, T., Takahashi, Y., Takamura, M., Takeda, M., Takeishi, R., Taketa, A., Takita, M., Tameda, Y., Tanaka, M., Tanaka, K., Tanaka, H., Thomas, S. B., Thomson, G. B., Tinyakov, P., Tirone, A. H., Tkachev, I., Tokuno, H., Tomida, T., Troitsky, S., Tsunesada, Y., Tsutsumi, K., Uchihori, Y., Udo, S., Urban, F., Wong, T., Yamane, R., Yamaoka, H., Yamazaki, K., Yang, J., Yashiro, K., Yoneda, Y., Yoshida, S., Yoshii, H., Zollinger, R., and Zundel, Z.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Cosmic rays in the energy range $10^{18.0}$ - $10^{18.5}$ eV are thought to have a light, probably protonic, composition. To study their origin one can search for anisotropy in their arrival directions. Extragalactic cosmic rays should be isotropic, but galactic cosmic rays of this type should be seen mostly along the galactic plane, and there should be a shortage of events coming from directions near the galactic anticenter. This is due to the fact that, under the influence of the galactic magnetic field, the transition from ballistic to diffusive behavior is well advanced, and this qualitative picture persists over the whole energy range. Guided by models of the galactic magnetic field that indicate that the enhancement along the galactic plane should have a standard deviation of about 20$^\circ$ in galactic latitude, and the deficit in the galactic anticenter direction should have a standard deviation of about 50$^\circ$ in galactic longitude, we use the data of the Telescope Array surface detector in $10^{18.0}$ to $10^{18.5}$ eV energy range to search for these effects. The data are isotropic. Neither an enhancement along the galactic plane nor a deficit in the galactic anticenter direction is found. Using these data we place an upper limit on the fraction of EeV cosmic rays of galactic origin at 1.3% at 95% confidence level.

Published
2016
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27. Impacts of B-factory measurements on determination of fragmentation functions from electron-positron annihilation data

Author

Hirai, M., Kawamura, H., Kumano, S., and Saito, K.

Subjects
High Energy Physics - Phenomenology, High Energy Physics - Experiment, Nuclear Experiment, Nuclear Theory
Abstract

Fragmentation functions are determined for the pion and kaon by global analyses of charged-hadron production data in electron-positron annihilation. Accurate measurements were reported by the Belle and BaBar collaborations for the fragmentation functions at the center-of-mass energies of 10.52 GeV and 10.54 GeV, respectively, at the KEK and SLAC B factories, whereas other available $e^+e^-$ measurements were mostly done at higher energies, mainly at the $Z$ mass of 91.2 GeV. There is a possibility that gluon fragmentation functions, as well as quark fragmentation functions, are accurately determined by scaling violation. We report our global analysis of the fragmentation functions especially to show impacts of the B-factory measurements on the fragmentation function determination. Our results indicate that the fragmentation functions are determined more accurately not only by the scaling violation but also by high-statistical nature of the Belle and BaBar data. However, there are some tensions between the Belle and BaBar data in comparison with previous measurements. We also explain how the flavor dependence of quark fragmentation functions and the gluon function are separated by using measurements at different $Q^2$ values. In particular, the electric and weak changes are different depending on the quark type, so that a light-quark flavor separation also became possible in principle due to the precise data at both $\sqrt{s}\simeq 10.5$ GeV and 91.2 GeV., Comment: 19 pages, 5 style files, 1 logo file, 8 eps figures, Progress of Theoretical and Experimental Physics (PTEP) in press

Published
2016

28. Insights into the emission of the blazar 1ES 1011+496 through unprecedented broadband observations during 2011 and 2012

Author

Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Arcaro, C., Babic, A., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de O. na, Mendez, C. Delgado, Di Pierro, F., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinović, N., noz, A. González Mu., Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Will, M., Zanin, R., Buson, S., D'Ammando, F., Lähteenmäki, A., Hovatta, T., Kovalev, Y. Y., Lister, M. L., Max-Moerbeck, W., Mundell, C., Pushkarev, A. B., Rastorgueva-Foi, E., Readhead, A. C. S., Richards, J. L., Tammi, J., Sanchez, D. A., Tornikoski, M., Savolainen, T., and Steele, I.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

1ES 1011+496 $(z=0.212)$ was discovered in very high energy (VHE, E >100 GeV) $\gamma$-rays with MAGIC in 2007. The absence of simultaneous data at lower energies led to a rather incomplete characterization of the broadband spectral energy distribution (SED). We study the source properties and the emission mechanisms, probing whether a simple one-zone synchrotron-self-Compton (SSC) scenario is able to explain the observed broadband spectrum. We analyzed VHE to radio data from 2011 and 2012 collected by MAGIC, $Fermi$-LAT, $Swift$, KVA, OVRO, and Mets\"ahovi in addition to optical polarimetry data and radio maps from the Liverpool Telescope and MOJAVE. The VHE spectrum was fit with a simple power law with a photon index of $3.69\pm0.22$ and a flux above 150 GeV of $(1.46\pm0.16)\times10^{-11}$ ph cm$^{-2}$ s$^{-1}$. 1ES 1011+496 was found to be in a generally quiescent state at all observed wavelengths, showing only moderate variability from radio to X-rays. A low degree of polarization of less than 10% was measured in optical, while some bright features polarized up to 60% were observed in the radio jet. A similar trend in the rotation of the electric vector position angle was found in optical and radio. The radio maps indicated a superluminal motion of $1.8\pm0.4\,c$, which is the highest speed statistically significantly measured so far in a high-frequency-peaked BL Lac. For the first time, the high-energy bump in the broadband SED of 1ES 1011+496 could be fully characterized from 0.1 GeV to 1 TeV which permitted a more reliable interpretation within the one-zone SSC scenario. The polarimetry data suggest that at least part of the optical emission has its origin in some of the bright radio features, while the low polarization in optical might be due to the contribution of parts of the radio jet with different orientations of the magnetic field to the optical emission., Comment: 14 pages, 7 figures

Published
2016
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30. Terrestrial ecosystem model performance in simulating productivity and its vulnerability to climate change in the northern permafrost region

Author

Xia, J, McGuire, AD, Lawrence, D, Burke, E, Chen, G, Chen, X, Delire, C, Koven, C, MacDougall, A, Peng, S, Rinke, A, Saito, K, Zhang, W, Alkama, R, Bohn, TJ, Ciais, P, Decharme, B, Gouttevin, I, Hajima, T, Hayes, DJ, Huang, K, Ji, D, Krinner, G, Lettenmaier, DP, Miller, PA, Moore, JC, Smith, B, Sueyoshi, T, Shi, Z, Yan, L, Liang, J, Jiang, L, Zhang, Q, and Luo, Y

Subjects
Geophysics
Abstract

Realistic projection of future climate-carbon (C) cycle feedbacks requires better understanding and an improved representation of the C cycle in permafrost regions in the current generation of Earth system models. Here we evaluated 10 terrestrial ecosystem models for their estimates of net primary productivity (NPP) and responses to historical climate change in permafrost regions in the Northern Hemisphere. In comparison with the satellite estimate from the Moderate Resolution Imaging Spectroradiometer (MODIS; 246 ± 6 g C m−2 yr−1), most models produced higher NPP (309 ± 12 g C m−2 yr−1) over the permafrost region during 2000–2009. By comparing the simulated gross primary productivity (GPP) with a flux tower-based database, we found that although mean GPP among the models was only overestimated by 10% over 1982–2009, there was a twofold discrepancy among models (380 to 800 g C m−2 yr−1), which mainly resulted from differences in simulated maximum monthly GPP (GPPmax). Most models overestimated C use efficiency (CUE) as compared to observations at both regional and site levels. Further analysis shows that model variability of GPP and CUE are nonlinearly correlated to variability in specific leaf area and the maximum rate of carboxylation by the enzyme Rubisco at 25°C (Vcmax_25), respectively. The models also varied in their sensitivities of NPP, GPP, and CUE to historical changes in climate and atmospheric CO2 concentration. These results indicate that model predictive ability of the C cycle in permafrost regions can be improved by better representation of the processes controlling CUE and GPPmax as well as their sensitivity to climate change.

Published
2017

32. First NuSTAR Observations of Mrk 501 within a Radio to TeV Multi-Instrument Campaign

Author

Furniss, A., Noda, K., Boggs, S., Chiang, J., Christensen, F., Craig, W., Giommi, P ., Hailey, C., Harisson, F., Madejski, G., Nalewajko, K., Perri, M., Stern, D., Urry, M., Verrecchia, F., Zhang, W., Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., de Almeida, U. Barres, Barrio, J. A., Gonzalez, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de Ona, Mendez, C. Delgado, Di Pierro, F., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Glawion, D. Eisenacher, Elsaesser, D., Fernandez-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., Lopez, R. J. Garcia, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giammaria, P., Godinovic, N., Munoz, A. Gonzalez, Guberman, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kellermann, H., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Lorenz, E., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martinez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Nakajima, D., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nilsson, K., Nishijima, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribo, M., Rico, J., Garcia, J. Rodriguez, Saito, T., Saito, K., Satalecka, K., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpaa, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Will, M., Zanin, R., Archer, A., Benbow, W., Bird, R., Biteau, J., Bugaev, V., Cardenzana, J. V, Cerruti, M., Chen, X., Ciupik, L., Connolly, M. P., Cui, W., Dickinson, H. J., Dumm, J., Eisch, J. D., Falcone, A., Feng, Q., Finley, J. P., Fleischhack, H., Fortin, P., Fortson, L., Gerard, L., Gillanders, G. H., Griffin, S., Griffiths, S. T., Grube, J., Gyuk, G., Haakansson, N., Holder, J., Humensky, T. B., Johnson, C. A., Kaaret, P., Kertzman, M., Kieda, D., Krause, M., Krennrich, F., Lang, M. J., Lin, T. T. Y., Maier, G., McArthur, S., McCann, A., Meagher, K., Moriarty, P., Mukherjee, R., Nieto, D., de Bhroithe, A. O'Faolain, Ong, R. A., Park, N., Petry, D., Pohl, M., Popkow, A., Ragan, K., Ratliff, G., Reyes, L. C., Reynolds, P. T., Richards, G. T., Roache, E., Santander, M., Sembroski, G. H., Shahinyan, K., Staszak, D., Telezhinsky, I., Tucci, J. V., Tyler, J., Vassiliev, V. V., Wakely, S. P., Weiner, O. M., Weinstein, A., Wilhelm, A., Williams, D. A., Zitzer, B., Fuhrmann, O. Vince L., Angelakis, E., Karamanavis, V., Myserlis, I., Krichbaum, T. P., Zensus, J. A., Ungerechts, H., Sievers, A., Bachev, R., Bottcher, M., Chen, W. P., Damljanovic, G., Eswaraiah, C., Guver, T., Hovatta, T., Hughes, Z., Ibryamov, S. . I., Joner, M. D., Jordan, B., Jorstad, S. G., Joshi, M., Kataoka, J., Kurtanidze, O. M., Kurtanidze, S. O., Lahteenmaki, A., Latev, G., Lin, H. C., Larionov, V. M., Mokrushina, A. A., Morozova, D. A., Nikolashvili, M. G., Raiteri, C. M., Ramakrishnan, V., Readhead, A. C. R., Sadun, A. C., Sigua, L. A., Semkov, E. H., Strigachev, A., Tammi, J., Tornikoski, M., Troitsky, Y. V. Troitskaya I. S., and Villata, M.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 1 April and 10 August 2013, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope (LAT), Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Mets\"ahovi and the F-Gamma consortium. Some of the MAGIC observations were affected by a sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a LIDAR (LIght Detection And Ranging) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) shows evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton model to five simultaneous broadband spectral energy distributions. We find that the synchrotron self-Compton model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission., Comment: Accepted for publication in ApJ

Published
2015
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33. CTA Contributions to the 34th International Cosmic Ray Conference (ICRC2015)

Author

Consortium, The CTA, Abchiche, A., Abeysekara, U., Abril, Ó., Acero, F., Acharya, B. S., Actis, M., Agnetta, G., Aguilar, J. A., Aharonian, F., Akhperjanian, A., Albert, A., Alcubierre, M., Alfaro, R., Aliu, E., Allafort, A. J., Allan, D., Allekotte, I., Aloisio, R., Amans, J. -P., Amato, E., Ambrogi, L., Ambrosi, G., Ambrosio, M., Anderson, J., Anduze, M., Angüner, E. O., Antolini, E., Antonelli, L. A., Antonucci, M., Antonuccio, V., Antoranz, P., Aramo, C., Aravantinos, A., Argan, A., Armstrong, T., Arnaldi, H., Arnold, L., Arrabito, L., Arrieta, M., Asano, K., Asorey, H. G., Aune, T., Singh, C. B., Babic, A., Backes, M., Bais, A., Bajtlik, S., Balazs, C., Balbo, M., Balis, D., Balkowski, C., Ballester, O., Ballet, J., Balzer, A., Bamba, A., Bandiera, R., Barber, A., Barbier, C., Barceló, M., Barnacka, A., de Almeida, U. Barres, Barrio, J. A., Basso, S., Bastieri, D., Bauer, C., Baushev, A., Becciani, U., Becherini, Y., Tjus, J. Becker, Beckmann, V., Bednarek, W., Benbow, W., Ventura, D. Benedico, Berdugo, J., Berge, D., Bernardini, E., Bernhard, S., Bernlöhr, K., Bertucci, B., Besel, M. -A., Bhatt, N., Bhattacharjee, P., Bhattachryya, S., Biasuzzi, B., Bicknell, G., Bigongiari, C., Biland, A., Billotta, S., Bilnik, W., Biondo, B., Bird, T., Birsin, E., Bissaldi, E., Biteau, J., Bitossi, M., Bigas, O. Blanch, Blasi, P., Boehm, C., Bogacz, L., Bogdan, M., Bohacova, M., Boisson, C., Gargallo, J. Boix, Bolmont, J., Bonanno, G., Bonardi, A., Bonifacio, P., Bonnoli, G., Borkowski, J., Bose, R., Bosnjak, Z., Bottani, A., Böttcher, M., Bousquet, J. -J., Boutonnet, C., Bouyjou, F., Braiding, C., Brandt, L., Brau-Nogué, S., Bregeon, J., Bretz, T., Briggs, M., Brigida, M., Bringmann, T., Brisken, W., Brocato, E., Brook, P., Brown, A. M., Brun, P., Brunetti, G., Brunetti, L., Bruno, P., Bryan, M., Buanes, T., Bucciantini, N., Buchholtz, G., Buckley, J., Bugaev, V., Bühler, R., Bulgarelli, A., Bulik, T., Burton, M., Burtovoi, A., Busetto, G., Buson, S., Buss, J., Byrum, K., Cameron, R., Camprecios, J., Canelli, F., Canestrari, R., Cantu, S., Capalbi, M., Capasso, M., Capobianco, G., Caraveo, P., Cardenzana, J., Carius, S., Carlile, C., Carmona, E., Carosi, A., Carosi, R., Carr, J., Carroll, M., Carter, J., Carton, P. -H., Caruso, R., Casandjian, J. -M., Casanova, S., Cascone, E., Casiraghi, M., Castellina, A., Catalano, O., Catalanotti, S., Cavazzani, S., Cazaux, S., Cefalà, M., Cerchiara, P., Cereda, M., Cerruti, M., Chabanne, E., Chadwick, P., Champion, C., Chaty, S., Chaves, R., Cheimets, P., Chen, A., Chen, X., Chernyakova, M., Chiappetti, L., Chikawa, M., Chinn, D., Chitnis, V. R., Cho, N., Christov, A., Chudoba, J., Cieślar, M., Cillis, A., Ciocci, M. A., Clay, R., Cohen-Tanugi, J., Colafrancesco, S., Colin, P., Colombo, E., Colome, J., Colonges, S., Compin, M., Conforti, V., Connaughton, V., Connell, S., Conrad, J., Contreras, J. L., Coppi, P., Corbel, S., Coridian, J., Corona, P., Corti, D., Cortina, J., Cossio, L., Costa, A., Costantini, H., Cotter, G., Courty, B., Covino, S., Covone, G., Crimi, G., Criswell, S. J., Crocker, R., Croston, J., Cusumano, G., Da Vela, P., Dale, Ø., D'Ammando, F., Dang, D., Daniel, M., Davids, I., Dawson, B., Dazzi, F., Costa, B. de Aguiar, De Angelis, A., Cardoso, R. F. de Araujo, De Caprio, V., De Cesare, G., De Franco, A., De Frondat, F., Pino, E. M. de Gouveia Dal, de la Calle, I., De La Vega, G. A., Lopez, R. de los Reyes, De Lotto, B., De Luca, A., Neto, J. R. 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A., Ottaway, D., Otte, N., Oya, I., Ozieblo, A., Padovani, M., Pagano, I., Paiano, S., Paizis, A., Palacio, J., Palatka, M., Pallotta, J., Panagiotidis, K., Panazol, J. -L., Paneque, D., Panter, M., Panzera, M. R., Paoletti, R., Paolillo, M., Papayannis, A., Papyan, G., Paravac, A., Paredes, J. M., Pareschi, G., Park, N., Parsons, D., Paśko, P., Pavy, S., Arribas, M. Paz, Pech, M., Peck, A., Pedaletti, G., Peet, S., Pelassa, V., Pelat, D., Peres, C., Perez, M. d. C., Perri, L., Persic, M., Petrashyk, A., Petrucci, P. -O., Peyaud, B., Pfeifer, M., Pfeiffer, G., Piano, G., Pichel, A., Pieloth, D., Pierbattista, M., Pierre, E., de Pinho, F. Pinto, García, C. Pio, Piret, Y., Pita, S., Planes, A., Platino, M., Platos, Ł., Platzer, R., Podkladkin, S., Pogosyan, L., Pohl, M., Poinsignon, P., Ponz, J. D., Porcelli, A., Potter, W., Poulios, S., Poutanen, J., Prandini, E., Prast, J., Preece, R., Profeti, F., Prokhorov, D., Prokoph, H., Prouza, M., Proyetti, M., Pruchniewicz, R., Pueschel, E., Pühlhofer, G., Puljak, I., Punch, M., Pyzioł, R., Queiroz, F., Quel, E. J., Quinn, J., Quirrenbach, A., Racero, E., Räck, T., Rafalski, J., Rafighi, I., Rainò, S., Rajda, P. J., Rameez, M., Rando, R., Rannot, R. C., Rataj, M., Rateau, S., Ravel, T., Ravignani, D., Razzaque, S., Reardon, P., Reimann, O., Reimer, A., Reimer, O., Reitberger, K., Renaud, M., Renner, S., Reposeur, T., Rettig, R., Reville, B., Rhode, W., Ribeiro, D., Ribó, M., Richards, G., Richer, M. G., Rico, J., Ridky, J., Rieger, F., Ringegni, P., Ristori, P. R., Rivière, A., Rivoire, S., Roache, E., Rodeghiero, G., Rodriguez, J., Fernandez, G. Rodriguez, Vázquez, J. J. Rodríguez, Rogers, T., Rojas, G., Romano, P., Rodriguez, M. P. Romay, Romeo, G., Romero, G. E., Roncadelli, M., Rose, J., Rosen, S., Lees, S. Rosier, Ross, D., Rossiter, P., Rouaix, G., Rousselle, J., Rovero, A. C., Rowell, G., Roy, F., Royer, S., Różańska, A., Rudak, B., Rugliancich, A., Rulten, C., Rupiński, M., Russo, F., Rutkowski, K., Saavedra, O., Sabatini, S., Sacco, B., Saemann, E. O., Saggion, A., Saha, L., Sahakian, V., Saito, K., Saito, T., Sakaki, N., Salega, M., Salek, D., Salgado, J., Salini, A., Sanchez, D., Sanchez, F., Sanchez-Conde, M., Sandaker, H., Sandoval, A., Sangiorgi, P., Sanguillon, M., Sano, H., Santander, M., Santangelo, A., Santos, E. M., Santos-Lima, R., Sanuy, A., Sapozhnikov, L., Sarkar, S., Satalecka, K., Savalle, R., Sawada, M., Sayède, F., Schafer, J., Schanne, S., Schanz, T., Schioppa, E. J., Schlenstedt, S., Schlickeiser, R., Schmidt, T., Schmoll, J., Schneider, M., Schovanek, P., Schubert, A., Schultz, C., Schultze, J., Schulz, A., Schulz, S., Schure, K., Schussler, F., Schwab, T., Schwanke, U., Schwarz, J., Schweizer, T., Schwemmer, S., Schwendicke, U., Schwerdt, C., Segreto, A., Seiradakis, J. -H., Sembroski, G. H., Semikoz, D., Serre, N., Servillat, M., Seweryn, K., Shafi, N., Sharma, M., Shayduk, M., Shellard, R. C., Shibata, T., Pandeni, K. Shiningayamwe, Shukla, A., Shum, E., Sidoli, L., Sidz, M., Sieiro, J., Siejkowski, H., Silk, J., Sillanpää, A., Simone, D., Singh, B. B., Sinha, A., Sironi, G., Sitarek, J., Sizun, P., Slyusar, V., Smith, A., Smith, J., Sobczyńska, D., Sol, H., Sottile, G., Sowiński, M., Spanier, F., Spengler, G., Spiga, D., Stadler, R., Stahl, O., Stamatescu, V., Stamerra, A., Stanič, S., Starling, R., Stawarz, Ł., Steenkamp, R., Stefanik, S., Stegmann, C., Steiner, S., Stella, C., Stergioulas, N., Sternberger, R., Sterzel, M., Stevenson, B., Stinzing, F., Stodulska, M., Stodulski, M., Stolarczyk, T., Straumann, U., Strazzeri, E., Stringhetti, L., Strzys, M., Stuik, R., Sulanke, K. -H., Supanitsky, A. D., Suric, T., Sushch, I., Sutcliffe, P., Sykes, J., Szanecki, M., Szepieniec, T., Szwarnog, P., Tacchini, A., Tachihara, K., Tagliaferri, G., Tajima, H., Takahashi, H., Takahashi, K., Takahashi, M., Takalo, L., Takami, H., Talbot, G., Tammi, J., Tanaka, M., Tanaka, S., Tanaka, T., Tanaka, Y., Tanci, C., Tarantino, E., Tavani, M., Tavecchio, F., Tavernet, J. -P., Tayabaly, K., Tejedor, L. A., Telezhinsky, I., Temme, F., Temnikov, P., Tenzer, C., Terada, Y., Terrier, R., Tescaro, D., Teshima, M., Testa, V., Tezier, D., Thayer, J., Thomas, V., Thornhill, J., Thuermann, D., Tibaldo, L., Tibolla, O., Tiengo, A., Tijsseling, G., Timpanaro, M. C., Tluczykont, M., Peixoto, C. J. Todero, Tokanai, F., Tokarz, M., Toma, K., Tomastik, J., Tomono, Y., Tonachini, A., Tonev, D., Torii, K., Tornikoski, M., Torres, D. F., Torres, M., Torresi, E., Toscano, S., Toso, G., Tosti, G., Totani, T., Tothill, N., Toussenel, F., Tovmassian, G., Townsley, C., Toyama, T., Travnicek, P., Trifoglio, M., Pujadas, I. Troyano, Trzeciak, M., Tsinganos, K., Tsubone, Y., Tsuchiya, Y., Tsujimoto, S., Tsuru, T., Uchiyama, Y., Umana, G., Umetsu, Y., Underwood, C., Upadhya, S. S., Uslenghi, M., Vagnetti, F., Valdes-Galicia, J., Vallania, P., Vallejo, G., Valore, L., van Driel, W., van Eldik, C., van Soelen, B., Vandenbroucke, J., Vanderwalt, J., Vasileiadis, G., Vassiliev, V., Acosta, M. L. Vázquez, Vecchi, M., Vegas, I., Veitch, P., Venema, L., Venter, C., Vercellone, S., Vergani, S., Verma, K., Verzi, V., Vettolani, G. P., Viana, A., Vicha, J., Videla, M., Vigorito, C., Vincent, P., Vincent, S., Vink, J., Vittorini, V., Vlahakis, N., Vlahos, L., Voelk, H., Vogler, P., Voisin, V., Vollhardt, A., Volpicelli, A., Vorobiov, S., Vovk, I., Vu, L. V., Wagner, R., Wagner, R. M., Wagner, R. G., Wagner, S. J., Wakely, S. P., Walter, R., Walther, T., Ward, J. E., Ward, M., Warda, K., Warwick, R., Wassberg, S., Watson, J., Wawer, P., Wawrzaszek, R., Webb, N., Wegner, P., Weinstein, A., Weitzel, Q., Wells, R., Werner, F., Werner, M., Wetteskind, H., White, M., White, R., Więcek, M., Wierzcholska, A., Wiesand, S., Wijers, R., Wild, N., Wilhelm, A., Wilkinson, M., Will, M., Williams, D. A., Williams, J. T., Willingale, R., Winde, M., Winiarski, K., Winkler, H., Wischnewski, R., Wojcik, P., Wolf, D., Wood, M., Wörnlein, A., Wu, E., Wu, T., Yadav, K. K., Yamamoto, H., Yamamoto, T., Yamazaki, R., Yanagita, S., Yang, L., Yebras, J. M., Yelos, D., Yeung, W., Yoshida, A., Yoshida, T., Yoshiike, S., Yoshikoshi, T., Yu, P., Zabalza, V., Zacharias, M., Zaharijas, G., Zajczyk, A., Zampieri, L., Zandanel, F., Zanin, R., Sanchez, R. Zanmar, Zavrtanik, D., Zavrtanik, M., Zdziarski, A., Zech, A., Zechlin, H., Zhao, A., Ziegler, A., Ziemann, J., Ziętara, K., Ziółkowski, J., Zitelli, V., Zoli, A., Zurbach, C., and Żychowski, P.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

List of contributions from the CTA Consortium presented at the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The Netherlands., Comment: Index of CTA conference proceedings at the ICRC2015, The Hague (The Netherlands). v1: placeholder with no arXiv links yet, to be replaced once individual contributions have been all submitted; v2: final with arXiv links to all CTA contributions and full author list

Published
2015

34. Very-high-energy {\gamma}-ray observations of novae and dwarf novae with the MAGIC telescopes

Author

MAGIC Collaboration, Ahnen, M. L., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Banerjee, B., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Chatterjee, A., Clavero, R., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de Oña, Mendez, C. Delgado, Di Pierro, F., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Glawion, D. Eisenacher, Elsaesser, D., Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giammaria, P., Godinović, N., Muñoz, A. González, Guberman, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kellermann, H., Kodani, K., Konno, Y., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Majumdar, P., Makariev, M., Mallot, K., Maneva, G., Manganaro, M., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Nakajima, D., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palacio, J., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Saito, T., Saito, K., Satalecka, K., Scapin, V., Schultz, C., Schweizer, T., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Verguilov, V., Vovk, I., Will, M., Zanin, R., Desiante, R., and Hays, E.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Context. In the last five years the Fermi Large Area Telescope (LAT) instrument detected GeV {\gamma}-ray emission from five novae. The GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a shock. In this case it is expected that protons in the same conditions can be accelerated to much higher energies. Consequently they may produce a second component in the {\gamma}-ray spectrum at TeV energies. Aims. We aim to explore the very-high-energy domain to search for {\gamma}-ray emission above 50 GeV and to shed light on the acceleration process of leptons and hadrons in nova explosions. Methods. We have performed observations with the MAGIC telescopes of the classical nova V339 Del shortly after the 2013 outburst, triggered by optical and subsequent GeV {\gamma}-ray detec- tions. We also briefly report on VHE observations of the symbiotic nova YY Her and the dwarf nova ASASSN-13ax. We complement the TeV MAGIC observations with the analysis of con- temporaneous Fermi-LAT data of the sources. The TeV and GeV observations are compared in order to evaluate the acceleration parameters for leptons and hadrons. Results. No significant TeV emission was found from the studied sources. We computed upper limits on the spectrum and night-by-night flux. The combined GeV and TeV observations of V339 Del limit the ratio of proton to electron luminosities to Lp<~0.15 Le., Comment: 7 pages, 2 figures, accepted for publication in A&A

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2015
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35. MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

Author

MAGIC Collaboration, Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de O. na, Mendez, C. Delgado, Di Pierro, F., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fernández-Barral, A., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinović, N., noz, A. González Mu., Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Neustroev, V., Niedzwiecki, A., Rosillo, M. Nievas, Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Stamerra, A., Steinbring, T., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Will, M., Zanin, R., Berger, K., Buson, S., D'Ammando, F., Gasparrini, D., Hovatta, T., Max-Moerbeck, W., Readhead, A., and Richards, J.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The high-frequency-peaked BL Lac (HBL) 1ES 0806+524 (z = 0.138) was discovered in VHE $\gamma$ rays in 2008. Until now, the broad-band spectrum of 1ES 0806+524 has been only poorly characterized, in particular at high energies. We analysed multiwavelength observations from $\gamma$ rays to radio performed from 2011 January to March, which were triggered by the high activity detected at optical frequencies. These observations constitute the most precise determination of the broad-band emission of 1ES 0806+524 to date. The stereoscopic MAGIC observations yielded a $\gamma$-ray signal above 250 GeV of $(3.7 \pm 0.7)$ per cent of the Crab Nebula flux with a statistical significance of 9.9 $\sigma$. The multiwavelength observations showed significant variability in essentially all energy bands, including a VHE $\gamma$-ray flare that lasted less than one night, which provided unprecedented evidence for short-term variability in 1ES 0806+524. The spectrum of this flare is well described by a power law with a photon index of $2.97 \pm 0.29$ between $\sim$150 GeV and 1 TeV and an integral flux of $(9.3 \pm 1.9)$ per cent of the Crab Nebula flux above 250 GeV. The spectrum during the non-flaring VHE activity is compatible with the only available VHE observation performed in 2008 with VERITAS when the source was in a low optical state. The broad-band spectral energy distribution can be described with a one-zone Synchrotron Self Compton model with parameters typical for HBLs, indicating that 1ES 0806+524 is not substantially different from the HBLs previously detected., Comment: 12 pages, 8 figures, 3 tables, accepted 2015 April 20 for publication in Monthly Notices of the Royal Astronomical Society Main Journal

Published
2015
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36. The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies

Author

MAGIC Collaboration, Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Fidalgo, D. Carreto, Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Farina, E., Ferenc, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giavitto, G., Godinović, N., noz, A. González Mu\, Gozzini, S. R., Hadamek, A., Hadasch, D., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Longo, F., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Meucci, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Nowak, N., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Partini, S., Persic, M., Prada, F., Moroni, P. G. Prada, Prandini, E., Preziuso, S., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saggion, A., Saito, K., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Storz, J., Sun, S., Surić, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Zandanel, F., Zanin, R., collaboration, VERITAS, Archambault, S., Behera, B., Beilicke, M., Benbow, W., Bird, R., Buckley, J. H., Bugaev, V., Cerruti, M., Chen, X., Ciupik, L., Collins-Hughes, E., Cui, W., Dumm, J., Eisch, J. D., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Fleischhack, H., Fortin, P., Fortson, L., Furniss, A., Griffin, S., Griffiths, S. T., Grube, J., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Humensky, T. B., Johnson, C. A., Kaaret, P., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Kumar, S., Lang, M. J., Maier, G., McArthur, S., Meagher, K., Moriarty, P., Mukherjee, R., Ong, R. A., Otte, A. N., Park, N., Pichel, A., Pohl, M., Popkow, A., Prokoph, H., Quinn, J., Ragan, K., Rajotte, J., Reynolds, P. T., Richards, G. T., Roache, E., Rovero, A. C., Sembroski, G. H., Shahinyan, K., Staszak, D., Telezhinsky, I., Theiling, M., Tucci, J. V., Tyler, J., Varlotta, A., Wakely, S. P., Weekes, T. C., Weinstein, A., Welsing, R., Wilhelm, A., Williams, D. A., Zitzer, B., collaborators, External, Villata, M., Raiteri, C., Aller, H. D., Aller, M. F., Chen, W. P., Jordan, B., Koptelova, E., Kurtanidze, O. M., Lähteenmäki, A., McBreen, B., Larionov, V. M., Lin, C. S., Nikolashvili, M. G., Angelakis, E., Capalbi, M., nana, A. Carrami\, Carrasco, L., Cassaro, P., Cesarini, A., Fuhrmann, L., Giroletti, M., Hovatta, T., Krichbaum, T. P., Krimm, H. A., Max-Moerbeck, W., Moody, J. W., Maccaferri, G., Mori, Y., Nestoras, I., Orlati, A., Pace, C., Pearson, R., Perri, M., Readhead, A. C. S., Richards, J. L., Sadun, A. C., Sakamoto, T., Tammi, J., Tornikoski, M., Yatsu, Y., and Zook, A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We performed a 4.5-month multi-instrument campaign (from radio to VHE gamma rays) on Mrk421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-correlation between optical/UV and X-rays extending over the duration of the campaign. The harder-when-brighter behavior in the X-ray spectra and the measured positive X-ray/VHE correlation during the 2009 multi-wavelength campaign suggests that the physical processes dominating the emission during non-flaring states have similarities with those occurring during flaring activity. In particular, this observation supports leptonic scenarios as being responsible for the emission of Mrk421 during non-flaring activity. Such a temporally extended X-ray/VHE correlation is not driven by any single flaring event, and hence is difficult to explain within the standard hadronic scenarios. The highest variability is observed in the X-ray band, which, within the one-zone synchrotron self-Compton scenario, indicates that the electron energy distribution is most variable at the highest energies., Comment: Accepted for publication in A&A, 18 pages, 14 figures (v2 has a small modification in the acknowledgments, and also corrects a typo in the field "author" in the metadata)

Published
2015
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37. MAGIC observations of MWC 656, the only known Be/BH system

Author

Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Bil, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de Oña, Mendez, C. Delgado, Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fidalgo, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hildebr, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Mir, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Neustroev, V., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Pr, E., ini, Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Will, M., Zanin, R., Casares, J., and Moldón, J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Context: MWC 656 has recently been established as the first observationally detected high-mass X-ray binary system containing a Be star and a black hole (BH). The system has been associated with a gamma-ray flaring event detected by the AGILE satellite in July 2010. Aims: Our aim is to evaluate if the MWC 656 gamma-ray emission extends to very high energy (VHE > 100 GeV) gamma rays. Methods. We have observed MWC 656 with the MAGIC telescopes for $\sim$23 hours during two observation periods: between May and June 2012 and June 2013. During the last period, observations were performed contemporaneously with X-ray (XMM-Newton) and optical (STELLA) instruments. Results: We have not detected the MWC 656 binary system at TeV energies with the MAGIC Telescopes in either of the two campaigns carried out. Upper limits (ULs) to the integral flux above 300 GeV have been set, as well as differential ULs at a level of $\sim$5% of the Crab Nebula flux. The results obtained from the MAGIC observations do not support persistent emission of very high energy gamma rays from this system at a level of 2.4% the Crab flux., Comment: Accepted for publication in A&A. 5 pages, 2 figures, 2 tables

Published
2015
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38. Black hole lightning due to particle acceleration at subhorizon scales

Author

MAGIC Collaboration, Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de Oña, Mendez, C. Delgado, Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Zanin, R., Kadler, M., Schulz, R., Ros, E., Bach, U., Krauß, F., and Wilms, J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Supermassive black holes with masses of millions to billions of solar masses are commonly found in the centers of galaxies. Astronomers seek to image jet formation using radio interferometry, but still suffer from insufficient angular resolution. An alternative method to resolve small structures is to measure the time variability of their emission. Here, we report on gamma-ray observations of the radio galaxy IC 310 obtained with the MAGIC telescopes revealing variability with doubling time scales faster than 4.8 min. Causality constrains the size of the emission region to be smaller than 20\% of the gravitational radius of its central black hole. We suggest that the emission is associated with pulsar-like particle acceleration by the electric field across a magnetospheric gap at the base of the radio jet., Comment: 19 pages, 10 figures, includes Supplementary Materials

Published
2014
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39. Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010

Author

The MAGIC Collaboration, Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Blanch, O., Boller, A., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de Oña, Mendez, C. Delgado, Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hildebrand, D., Hose, J., Hrupec, D., Hughes, G., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Sun, S., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Steinke, B., Storz, J., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Zanin, R., Collaboration, The VERITAS, Archambault, S., Archer, A., Beilicke, M., Benbow, W., Berger, K., Bird, R., Biteau, J., Buckley, J. H., Bugaev, V., Cerruti, M., Chen, X., Ciupik, L., Collins-Hughes, E., Cui, W., Eisch, J. D., Falcone, A., Feng, Q., Finley, J. P., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gillanders, G. H., Griffin, S., Gyuk, G., Håkansson, N., Holder, J., Johnson, C. A., Kaaret, P., Kar, P., Kertzman, M., Kieda, D., Lang, M. J., McArthur, S., McCann, A., Meagher, K., Millis, J., Moriarty, P., Ong, R. A., Otte, A. N., Perkins, J. S., Pichel, A., Pohl, M., Popkow, A., Prokoph, H., Pueschel, E., Ragan, K., Reyes, L. C., Reynolds, P. T., Richards, G. T., Roache, E., Rovero, A. C., Sembroski, G. H., Shahinyan, K., Staszak, D., Telezhinsky, I., Tucci, J. V., Tyler, J., Varlotta, A., Wakely, S. P., Welsing, R., Wilhelm, A., Williams, D. A., Collaborators, External, Buson, S., Finke, J., Villata, M., Raiteri, C., Aller, H. D., Aller, M. F., Cesarini, A., Chen, W. P., Gurwell, M. A., Jorstad, S. G., Kimeridze, G. N., Koptelova, E., Kurtanidze, O. M., Kurtanidze, S. O., Lähteenmäki, A., Larionov, V. M., Larionova, E. G., Lin, H. C., McBreen, B., Moody, J. W., Morozova, D. A., Marscher, A. P., Max-Moerbeck, W., Nikolashvili, M. G., Perri, M., Readhead, A. C. S., Richards, J. L., Ros, J. A., Sadun, A. C., Sakamoto, T., Sigua, L. A., Smith, P. S., Tornikoski, M., Troitsky, I. S., Wehrle, A. E., and Jordan, B.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

A flare from the TeV blazar Mrk 421, occurring in March 2010, was observed for 13 consecutive days from radio to very high energy (VHE, E > 100 GeV) gamma-rays with MAGIC, VERITAS, Whipple, FermiLAT, MAXI, RXTE, Swift, GASP-WEBT, and several optical and radio telescopes. We model the day-scale SEDs with one-zone and two-zone synchrotron self-Compton (SSC) models, investigate the physical parameters, and evaluate whether the observed broadband SED variability can be associated to variations in the relativistic particle population. Flux variability was remarkable in the X-ray and VHE bands while it was minor or not significant in the other bands. The one-zone SSC model can describe reasonably well the SED of each day for the 13 consecutive days. This flaring activity is also very well described by a two-zone SSC model, where one zone is responsible for the quiescent emission while the other smaller zone, which is spatially separated from the first one, contributes to the daily-variable emission occurring in X-rays and VHE gamma-rays. Both the one-zone SSC and the two-zone SSC models can describe the daily SEDs via the variation of only four or five model parameters, under the hypothesis that the variability is associated mostly to the underlying particle population. This shows that the particle acceleration and cooling mechanism producing the radiating particles could be the main one responsible for the broadband SED variations during the flaring episodes in blazars. The two-zone SSC model provides a better agreement to the observed SED at the narrow peaks of the low- and high-energy bumps during the highest activity, although the reported one-zone SSC model could be further improved by the variation of the parameters related to the emitting region itself ($\delta$, $B$ and $R$), in addition to the parameters related to the particle population., Comment: Published in A&A, 30 pages, 15 figures, 6 tables. Online-data: multi-wavelength light curves (data in Fig. 1) and broadband spectral energy distributions (the data in Figs. 6, and B1-B4) are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/578/A22. Corresponding authors: David Paneque (dpaneque@mpp.mpg.de), Shangyu Sun (sysun@mpp.mpg.de), Hajime Takami (takami@post.kek.jp)

Published
2014
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40. Discovery of very high energy gamma-ray emission from the blazar 1ES 0033+595 by the MAGIC telescopes

Author

Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Fidalgo, D. Carreto, Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Farina, E., Ferenc, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Hayashida, M., Herrera, J., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Meucci, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Nowak, N., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Partini, S., Persic, M., Prada, F., Moroni, P. G. Prada, Prandini, E., Preziuso, S., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saggion, A., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Storz, J., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Zandanel, F., Zanin, R., Tronconi, V., and Buson, S.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

The number of known very high energy (VHE) blazars is $\sim\,50$, which is very small in comparison to the number of blazars detected in other frequencies. This situation is a handicap for population studies of blazars, which emit about half of their luminosity in the $\gamma$-ray domain. Moreover, VHE blazars, if distant, allow for the study of the environment that the high-energy $\gamma$-rays traverse in their path towards the Earth, like the extragalactic background light (EBL) and the intergalactic magnetic field (IGMF), and hence they have a special interest for the astrophysics community. We present the first VHE detection of 1ES\,0033+595 with a statistical significance of 5.5\,$\sigma$. The VHE emission of this object is constant throughout the MAGIC observations (2009 August and October), and can be parameterized with a power law with an integral flux above 150 GeV of $(7.1\pm1.3)\times 10^{-12} {\mathrm{ph\,cm^{-2}\,s^{-1}}}$ and a photon index of ($3.8\pm0.7$). We model its spectral energy distribution (SED) as the result of inverse Compton scattering of synchrotron photons. For the study of the SED we used simultaneous optical R-band data from the KVA telescope, archival X-ray data by \textit{Swift} as well as \textit{INTEGRAL}, and simultaneous high energy (HE, $300$\,MeV~--~$10$\,GeV) $\gamma$-ray data from the \textit{Fermi} LAT observatory. Using the empirical approach of Prandini et al. (2010) and the \textit{Fermi}-LAT and MAGIC spectra for this object, we estimate the redshift of this source to be $0.34\pm0.08\pm0.05$. This is a relevant result because this source is possibly one of the ten most distant VHE blazars known to date, and with further (simultaneous) observations could play an important role in blazar population studies, as well as future constraints on the EBL and IGMF., Comment: Accepted to be published in MNRAS, 10 pages, 8 figures

Published
2014
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41. Multiwavelength observations of Mrk 501 in 2008

Author

MAGIC Collaboration, Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Fidalgo, D. Carreto, Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Farina, E., Ferenc, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giavitto, G., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadamek, A., Hadasch, D., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Knoetig, M. L., Krause, J., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Meucci, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Nowak, N., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Partini, S., Persic, M., Prada, F., Moroni, P. G. Prada, Prandini, E., Preziuso, S., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saggion, A., Saito, T., Saito, K., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Storz, J., Sun, S., Surić, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Zandanel, F., Zanin, R., Collaboration, VERITAS, Behera, B., Beilicke, M., Benbow, W., Bird, R., Bouvier, A., Bugaev, V., Cerruti, M., Chen, X., Ciupik, L., Collins-Hughes, E., Cui, W., Duke, C., Dumm, J., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Galante, N., Gillanders, G. H., Griffin, S., Griffiths, S. T., Grube, J., Gyuk, G., Hanna, D., Holder, J., Johnson, C. A., Kaaret, P., Kertzman, M., Kieda, D., Krawczynski, H., Lang, M. J., Madhavan, A. S, Maier, G., Majumdar, P., Meagher, K., Moriarty, P., Mukherjee, R., Nieto, D., de Bhróithe, A. O'Faoláin, Ong, R. A., Otte, A. N., Pichel, A., Pohl, M., Popkow, A., Prokoph, H., Quinn, J., Rajotte, J., Ratliff, G., Reyes, L. C., Reynolds, P. T., Richards, G. T., Roache, E., Sembroski, G. H., Shahinyan, K., Sheidaei, F., Smith, A. W., Staszak, D., Telezhinsky, I., Theiling, M., Tyler, J., Varlotta, A., Vincent, S., Wakely, S. P., Weekes, T. C., Welsing, R., Williams, D. A., Zajczyk, A., Zitzer, B., Collaborators, External, Villata, M., Raiteri, C. M., Ajello, M., Perri, M., Aller, H. D., Aller, M. F., Larionov, V. M., Efimova, N. V., Konstantinova, T. S., Kopatskaya, E. N., Chen, W. P., Koptelova, E., Hsiao, H. Y., Kurtanidze, O. M., Nikolashvili, M. G., Kimeridze, G. N., Jordan, B., Leto, P., Buemi, C. S., Trigilio, C., Umana, G., Lahtenmaki, A., Nieppola, E., Tornikoski, M., Sainio, J., Giroletti, M., Cesarini, A., Fuhrmann, L., Kovalev, Yu. A., and Kovalev, Y. Y.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Mrk 501 is one of the brightest blazars at TeV energies and has been extensively studied since its first VHE detection in 1996. Our goal is to characterize in detail the source gamma-ray emission, together with the radio-to-X-ray emission, during the non-flaring (low) activity, which is less often studied than the occasional flaring (high) activity. We organized a multiwavelength (MW) campaign on Mrk 501 between March and May 2008. This multi-instrument effort included the most sensitive VHE gamma-ray instruments in the northern hemisphere, namely the imaging atmospheric Cherenkov telescopes MAGIC and VERITAS, as well as Swift, RXTE, the F-GAMMA, GASP-WEBT, and other collaborations and instruments. Mrk 501 was found to be in a low state of activity during the campaign, with a VHE flux in the range of 10%-20% of the Crab nebula flux. Nevertheless, significant flux variations were detected with various instruments, with a trend of increasing variability with energy. The broadband spectral energy distribution during the two different emission states of the campaign can be adequately described within the homogeneous one-zone synchrotron self-Compton model, with the (slightly) higher state described by an increase in the electron number density. This agrees with previous studies of the broadband emission of this source during flaring and non-flaring states. We report for the first time a tentative X-ray-to-VHE correlation during a low VHE activity. Although marginally significant, this positive correlation between X-ray and VHE, which has been reported many times during flaring activity, suggests that the mechanisms that dominate the X-ray/VHE emission during non-flaring-activity are not substantially different from those that are responsible for the emission during flaring activity., Comment: Accepted for publication in A&A

Published
2014
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43. Evaluation of air-soil temperature relationships simulated by land surface models during winter across the permafrost region

Author

Wang, W, Rinke, A, Moore, JC, Ji, D, Cui, X, Peng, S, Lawrence, DM, McGuire, AD, Burke, EJ, Chen, X, Decharme, B, Koven, C, MacDougall, A, Saito, K, Zhang, W, Alkama, R, Bohn, TJ, Ciais, P, Delire, C, Gouttevin, I, Hajima, T, Krinner, G, Lettenmaier, DP, Miller, PA, Smith, B, Sueyoshi, T, and Sherstiukov, AB

Subjects
Meteorology & Atmospheric Sciences, Oceanography, Physical Geography and Environmental Geoscience
Abstract

A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyse simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models, and compare them with observations from 268 Russian stations. There are large cross-model differences in the simulated differences between near-surface soil and air temperatures (ΔT; 3 to 14 °C), in the sensitivity of soil-to-air temperature (0.13 to 0.96 °C °C-1), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, hence guide improvements to the model's conceptual structure and process parameterisations. Models with better performance apply multilayer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (13.19 to 15.77 million km2). However, there is not a simple relationship between the sophistication of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, because several other factors, such as soil depth used in the models, the treatment of soil organic matter content, hydrology and vegetation cover, also affect the simulated permafrost distribution.

Published
2016

44. Variability in the sensitivity among model simulations of permafrost and carbon dynamics in the permafrost region between 1960 and 2009

Author

McGuire, AD, Koven, C, Lawrence, DM, Clein, JS, Xia, J, Beer, C, Burke, E, Chen, G, Chen, X, Delire, C, Jafarov, E, MacDougall, AH, Marchenko, S, Nicolsky, D, Peng, S, Rinke, A, Saito, K, Zhang, W, Alkama, R, Bohn, TJ, Ciais, P, Decharme, B, Ekici, A, Gouttevin, I, Hajima, T, Hayes, DJ, Ji, D, Krinner, G, Lettenmaier, DP, Luo, Y, Miller, PA, Moore, JC, Romanovsky, V, Schädel, C, Schaefer, K, Schuur, EAG, Smith, B, Sueyoshi, T, and Zhuang, Q

Subjects
carbon cycle, climate change, permafrost, permafrost carbon feedback, sensitivity, soil carbon, Meteorology & Atmospheric Sciences, Atmospheric Sciences, Geochemistry, Oceanography
Abstract

A significant portion of the large amount of carbon (C) currently stored in soils of the permafrost region in the Northern Hemisphere has the potential to be emitted as the greenhouse gases CO2 and CH4 under a warmer climate. In this study we evaluated the variability in the sensitivity of permafrost and C in recent decades among land surface model simulations over the permafrost region between 1960 and 2009. The 15 model simulations all predict a loss of near-surface permafrost (within 3 m) area over the region, but there are large differences in the magnitude of the simulated rates of loss among the models (0.2 to 58.8 × 103 km2 yr−1). Sensitivity simulations indicated that changes in air temperature largely explained changes in permafrost area, although interactions among changes in other environmental variables also played a role. All of the models indicate that both vegetation and soil C storage together have increased by 156 to 954 Tg C yr−1 between 1960 and 2009 over the permafrost region even though model analyses indicate that warming alone would decrease soil C storage. Increases in gross primary production (GPP) largely explain the simulated increases in vegetation and soil C. The sensitivity of GPP to increases in atmospheric CO2 was the dominant cause of increases in GPP across the models, but comparison of simulated GPP trends across the 1982–2009 period with that of a global GPP data set indicates that all of the models overestimate the trend in GPP. Disturbance also appears to be an important factor affecting C storage, as models that consider disturbance had lower increases in C storage than models that did not consider disturbance. To improve the modeling of C in the permafrost region, there is the need for the modeling community to standardize structural representation of permafrost and carbon dynamics among models that are used to evaluate the permafrost C feedback and for the modeling and observational communities to jointly develop data sets and methodologies to more effectively benchmark models.

Published
2016

45. Diagnostic and model dependent uncertainty of simulated Tibetan permafrost area

Author

Wang, W, Rinke, A, Moore, JC, Cui, X, Ji, D, Li, Q, Zhang, N, Wang, C, Zhang, S, Lawrence, DM, McGuire, AD, Zhang, W, Delire, C, Koven, C, Saito, K, MacDougall, A, Burke, E, and Decharme, B

Subjects
Meteorology & Atmospheric Sciences, Oceanography, Physical Geography and Environmental Geoscience
Abstract

We perform a land-surface model intercomparison to investigate how the simulation of permafrost area on the Tibetan Plateau (TP) varies among six modern stand-alone land-surface models (CLM4.5, CoLM, ISBA, JULES, LPJ-GUESS, UVic). We also examine the variability in simulated permafrost area and distribution introduced by five different methods of diagnosing permafrost (from modeled monthly ground temperature, mean annual ground and air temperatures, air and surface frost indexes). There is good agreement (99 to 135 × 104km2) between the two diagnostic methods based on air temperature which are also consistent with the observation-based estimate of actual permafrost area (101 ×104km2). However the uncertainty (1 to 128 × 104km2) using the three methods that require simulation of ground temperature is much greater. Moreover simulated permafrost distribution on the TP is generally only fair to poor for these three methods (diagnosis of permafrost from monthly, and mean annual ground temperature, and surface frost index), while permafrost distribution using air-temperature-based methods is generally good. Model evaluation at field sites highlights specific problems in process simulations likely related to soil texture specification, vegetation types and snow cover. Models are particularly poor at simulating permafrost distribution using the definition that soil temperature remains at or below 0°C for 24 consecutive months, which requires reliable simulation of both mean annual ground temperatures and seasonal cycle, and hence is relatively demanding. Although models can produce better permafrost maps using mean annual ground temperature and surface frost index, analysis of simulated soil temperature profiles reveals substantial biases. The current generation of land-surface models need to reduce biases in simulated soil temperature profiles before reliable contemporary permafrost maps and predictions of changes in future permafrost distribution can be made for the Tibetan Plateau.

Published
2016

46. Simulated high-latitude soil thermal dynamics during the past 4 decades

Author

Peng, S, Ciais, P, Krinner, G, Wang, T, Gouttevin, I, McGuire, AD, Lawrence, D, Burke, E, Chen, X, Decharme, B, Koven, C, MacDougall, A, Rinke, A, Saito, K, Zhang, W, Alkama, R, Bohn, TJ, Delire, C, Hajima, T, Ji, D, Lettenmaier, DP, Miller, PA, Moore, JC, Smith, B, and Sueyoshi, T

Subjects
Earth Sciences, Atmospheric Sciences, Climate Action, Oceanography, Physical Geography and Environmental Geoscience, Meteorology & Atmospheric Sciences, Physical geography and environmental geoscience
Abstract

Soil temperature (Ts/change is a key indicator of the dynamics of permafrost. On seasonal and interannual timescales, the variability of Ts determines the activelayer depth, which regulates hydrological soil properties and biogeochemical processes. On the multi-decadal scale, increasing Ts not only drives permafrost thaw/retreat but can also trigger and accelerate the decomposition of soil organic carbon. The magnitude of permafrost carbon feedbacks is thus closely linked to the rate of change of soil thermal regimes. In this study, we used nine process-based ecosystem models with permafrost processes, all forced by different observation-based climate forcing during the period 1960-2000, to characterize the warming rate of Ts in permafrost regions. There is a large spread of Ts trends at 20 cm depth across the models, with trend values ranging from 0.010 ± 0.003 to 0.031 ± 0.005 °C yr-1. Most models show smaller increase in Ts with increasing depth. Air temperature (Ta/and longwave downward radiation (LWDR) are the main drivers of Ts trends, but their relative contributions differ amongst the models. Different trends of LWDR used in the forcing of models can explain 61 % of their differences in Ts trends, while trends of Ta only explain 5 % of the differences in Ts trends. Uncertain climate forcing contributes a larger uncertainty in Ts trends (0.021 ± 0.008 °C yr-1, mean ± standard deviation) than the uncertainty of model structure (0.012 ± 0.001 °C yr-1/, diagnosed from the range of response between different models, normalized to the same forcing. In addition, the loss rate of near-surface permafrost area, defined as total area where the maximum seasonal active-layer thickness (ALT) is less than 3 m loss rate, is found to be significantly correlated with the magnitude of the trends of Ts at 1 m depth across the models (R D-0:85, P = 0:003), but not with the initial total nearsurface permafrost area (R =-0:30, P = 0:438). The sensitivity of the total boreal near-surface permafrost area to Ts at 1 m is estimated to be of-2.80 ± 0.67 million km2 °C-1. Finally, by using two long-term LWDR data sets and relationships between trends of LWDR and Ts across models, we infer an observation-constrained total boreal near-surface permafrost area decrease comprising between 39 ± 14 × 103 and 75 ± 14 × 103 km2 yr-1 from 1960 to 2000. This corresponds to 9-18 % degradation of the current permafrost area.

Published
2016

48. The major upgrade of the MAGIC telescopes, Part I: The hardware improvements and the commissioning of the system

Author

MAGIC Collaboration, Aleksic, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barcelo, M., Barrio, J. A., Gonzalez, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Bitossi, M., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Cecchi, R., Colin, P., Colombo, E., Contreras, J. L., Corti, D., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de Ona, Mendez, C. Delgado, Dettlaff, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fidalgo, D., Fink, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., Lopez, R. J. Garcia, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giavitto, G., Godinovic, N., Munoz, A. Gonzalez, Gozzini, S. R., Haberer, W., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Illa, J. M., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lemus, J. L., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Lorca, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martinez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Negrello, M., Neustroev, V., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribo, M., Rico, J., Garcia, J. Rodriguez, Rugamer, S., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schlammer, J., Schmidl, S., Schweizer, T., Sillanpaa, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Tejedor, L. A., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Wetteskind, H., Will, M., and Zanin, R.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs) located on the Canary island of La Palma. The telescopes are designed to measure Cherenkov light from air showers initiated by gamma rays in the energy regime from around 50 GeV to more than 50 TeV. The two telescopes were built in 2004 and 2009, respectively, with different cameras, triggers and readout systems. In the years 2011-2012 the MAGIC collaboration undertook a major upgrade to make the stereoscopic system uniform, improving its overall performance and easing its maintenance. In particular, the camera, the receivers and the trigger of the first telescope were replaced and the readout of the two telescopes was upgraded. This paper (Part I) describes the details of the upgrade as well as the basic performance parameters of MAGIC such as raw data treatment, dead time of the system, linearity in the electronic chain and sources of noise. In Part II, we describe the physics performance of the upgraded system., Comment: 19 pages, 18 figures, accepted by Astroparticle Physics

Published
2014
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49. The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula

Author

MAGIC Collaboration, Aleksic, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., Barcelo, M., Barrio, J. A., Gonzalez, J. Becerra, Bednarek, W., Bernardini, E., Biasuzzi, B., Biland, A., Bitossi, M., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Cecchi, R., Colin, P., Colombo, E., Contreras, J. L., Corti, D., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Wilhelmi, E. de Ona, Mendez, C. Delgado, Dettlaff, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Fidalgo, D., Fink, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., Galindo, D., Lopez, R. J. Garcia, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Giavitto, G., Godinovic, N., Munoz, A. Gonzalez, Gozzini, S. R., Haberer, W., Hadasch, D., Hanabata, Y., Hayashida, M., Herrera, J., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Illa, J. M., Kadenius, V., Kellermann, H., Knoetig, M. L., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lemus, J. L., Lewandowska, N., Lindfors, E., Lombardi, S., Longo, F., Lopez, M., Lopez-Coto, R., Lopez-Oramas, A., Lorca, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martinez, M., Mazin, D., Menzel, U., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Negrello, M., Neustroev, V., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Persic, M., Poutanen, J., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reinthal, R., Rhode, W., Ribo, M., Rico, J., Garcia, J. Rodriguez, Rugamer, S., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schlammer, J., Schmidl, S., Schweizer, T., Shore, S. N., Sillanpaa, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Takalo, L., Takami, H., Tavecchio, F., Tejedor, L. A., Temnikov, P., Terzic, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Vogler, P., Wetteskind, H., Will, M., and Zanin, R.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma, Spain. During summer 2011 and 2012 it underwent a series of upgrades, involving the exchange of the MAGIC-I camera and its trigger system, as well as the upgrade of the readout system of both telescopes. We use observations of the Crab Nebula taken at low and medium zenith angles to assess the key performance parameters of the MAGIC stereo system. For low zenith angle observations, the standard trigger threshold of the MAGIC telescopes is ~50GeV. The integral sensitivity for point-like sources with Crab Nebula-like spectrum above 220GeV is (0.66+/-0.03)% of Crab Nebula flux in 50 h of observations. The angular resolution, defined as the sigma of a 2-dimensional Gaussian distribution, at those energies is < 0.07 degree, while the energy resolution is 16%. We also re-evaluate the effect of the systematic uncertainty on the data taken with the MAGIC telescopes after the upgrade. We estimate that the systematic uncertainties can be divided in the following components: < 15% in energy scale, 11-18% in flux normalization and +/-0.15 for the energy spectrum power-law slope., Comment: 21 pages, 25 figures, accepted for publication in Astroparticle Physics

Published
2014
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50. First broadband characterization and redshift determination of the VHE blazar MAGIC J2001+439

Author

MAGIC Collaboration, Aleksić, J., Ansoldi, S., Antonelli, L. A., Antoranz, P., Babic, A., Bangale, P., de Almeida, U. Barres, Barrio, J. A., González, J. Becerra, Bednarek, W., Bernardini, E., Biland, A., Blanch, O., Bonnefoy, S., Bonnoli, G., Borracci, F., Bretz, T., Carmona, E., Carosi, A., Fidalgo, D. Carreto, Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Da Vela, P., Dazzi, F., De Angelis, A., De Caneva, G., De Lotto, B., Mendez, C. Delgado, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Einecke, S., Eisenacher, D., Elsaesser, D., Farina, E., Ferenc, D., Fonseca, M. V., Font, L., Frantzen, K., Fruck, C., López, R. J. García, Garczarczyk, M., Terrats, D. Garrido, Gaug, M., Godinović, N., Muñoz, A. González, Gozzini, S. R., Hadasch, D., Hayashida, M., Herrera, J., Herrero, A., Hildebrand, D., Hose, J., Hrupec, D., Idec, W., Kadenius, V., Kellermann, H., Kodani, K., Konno, Y., Krause, J., Kubo, H., Kushida, J., La Barbera, A., Lelas, D., Lewandowska, N., Lindfors, E., Lombardi, S., López, M., López-Coto, R., López-Oramas, A., Lorenz, E., Lozano, I., Makariev, M., Mallot, K., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Marcote, B., Mariotti, M., Martínez, M., Mazin, D., Menzel, U., Meucci, M., Miranda, J. M., Mirzoyan, R., Moralejo, A., Munar-Adrover, P., Nakajima, D., Niedzwiecki, A., Nilsson, K., Nishijima, K., Noda, K., Nowak, N., Orito, R., Overkemping, A., Paiano, S., Palatiello, M., Paneque, D., Paoletti, R., Paredes, J. M., Paredes-Fortuny, X., Partini, S., Persic, M., Prada, F., Moroni, P. G. Prada, Prandini, E., Preziuso, S., Puljak, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Garcia, J. Rodriguez, Rügamer, S., Saggion, A., Saito, T., Saito, K., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shore, S. N., Sillanpää, A., Sitarek, J., Snidaric, I., Sobczynska, D., Spanier, F., Stamatescu, V., Stamerra, A., Steinbring, T., Storz, J., Strzys, M., Sun, S., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thaele, J., Tibolla, O., Torres, D. F., Toyama, T., Treves, A., Uellenbeck, M., Vogler, P., Wagner, R. M., Zandanel, F., Zanin, R., D'Ammando, F., Hovatta, T., Larionov, V. M., Max-Moerbeck, W., Perri, M., Readhead, A. C. S., Richards, J. L., Sakamoto, T., Schwartz, R. D., Verrecchia, F., and Reyes, L. C.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We aim to characterize the broadband emission from 2FGL J2001.1+4352, which has been associated with the unknown-redshift blazar MG4 J200112+4352. Based on its gamma-ray spectral properties, it was identified as a potential very high energy (VHE; E > 100 GeV) gamma-ray emitter. The source was observed with MAGIC first in 2009 and later in 2010 within a multi-instrument observation campaign. The MAGIC observations yielded 14.8 hours of good quality stereoscopic data. The object was monitored at radio, optical and gamma-ray energies during the years 2010 and 2011. The source, named MAGIC J2001+439, is detected for the first time at VHE with MAGIC at a statistical significance of 6.3 {\sigma} (E > 70 GeV) during a 1.3-hour long observation on 2010 July 16. The multi-instrument observations show variability in all energy bands with the highest amplitude of variability in the X-ray and VHE bands. We also organized deep imaging optical observations with the Nordic Optical Telescope in 2013 to determine the source redshift. We determine for the first time the redshift of this BL Lac object through the measurement of its host galaxy during low blazar activity. Using the observational evidence that the luminosities of BL Lac host galaxies are confined to a relatively narrow range, we obtain z = 0.18 +/- 0.04. Additionally, we use the Fermi-LAT and MAGIC gamma-ray spectra to provide an independent redshift estimation, z = 0.17 +/- 0.10. Using the former (more accurate) redshift value, we adequately describe the broadband emission with a one-zone SSC model for different activity states and interpret the few-day timescale variability as produced by changes in the high-energy component of the electron energy distribution., Comment: 17 pages, 15 figures, Accepted for publication in A&A

Published
2014
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